Documents published in 2023 : Scipedia

“IMPROVING THE METHODOLOGY OF TARIFF REGULATION AND ASSESSMENT OF THE TARIFF CONSEQUENCES OF LIBERALIZATION OF RELATIONS IN THE SPHERE OF HEAT SUPPLY»
O. Mozgovaya, B. Fayn, D. Agafonov

RUSSIAN PRESIDENTIAL ACADEMY OF NATIONAL ECONOMY AND PUBLIC ADMINISTRATION (2022). 19

Abstract
This paper presents the results of the scientific research "The Development of tariff regulation methodology and estimation of district heating liberalization effects”. The authors studied legislation of the price cap regulation on which the ‘No-MoreThan-Alternative-Boiler’ principle is based, constituting mechanisms of new economic relationships in the heating sector in Russia. The paper has studied the impact of the price cap regulation based on the ‘No-MoreThan-Alternative-Boiler’ principle established for the biggest unified heat supply companies operating in municipal areas where the heating market has completely transitioned to the new economic model as of the second half of 2021 (i.e. the transition period has ended). A lack of heat price explosion is noted; however, in 12 out of 15 unified heat supply companies studied, the conditions are in place for the consumer heating prices to rise faster than inflation in the next few years. According to the results of the research, the main problems of price cap regulation based on the ‘No-More-Than-Alternative-Boiler’ principle have been revealed, and practical recommendations for improving the mechanisms of ‘No-More-Than-Alternative-Boiler’ principle of the price regulation have been established.
Abstract
This paper presents the results of the scientific research "The Development of tariff regulation methodology and estimation of district heating liberalization effects”. [...]
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Review of foreign experience in assessing the impact of qualitative indicators on economic processes using vector autoregression models
S. Maria

RUSSIAN PRESIDENTIAL ACADEMY OF NATIONAL ECONOMY AND PUBLIC ADMINISTRATION (2022). 20

Abstract
This paper provides an overview of foreign experience in using panel data to assess various economic phenomena and processes. Note that this paper presents two types of models: panel vector autoregression model and vector autoregression model.
Abstract
This paper provides an overview of foreign experience in using panel data to assess various economic phenomena and processes. Note that this paper presents two types of models: [...]
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Melt Processing of Cellulose Nanofibers Reinforced PLA from a Sustainable Masterbatch Process
J. Cailloux, J. Raquez, G. Re, O. Santana, P. Dubois, M. Maspoch

Materiales Compuestos (2023). Vol. 03 - Comunicaciones Matcomp17 (2019), (Núm. 3 - Procesos de Fabricación II y Materiales Avanzados), 17

Abstract
In this study, cellulose nanofiber (CNF)-reinforced poly (lactic acid) (PLA) bionanocomposites were manufactured through industrially scalable equipments. The compatibility differences between hydrophobic PLA and hydrophilic CNF was counteracted using a water-based polyethylene glycol (PEG)/CNF masterbatch approach, hence minimizing CNF self-agglomeration during drying. Polarized light microscopy showed a progressive refinement of the CNF distribution into PLA upon increasing the PEG content. Rheological experiments provided further evidences about the efficiency of the PEG carrier sytem. Indeed the formation of strong CNF interactions or a three-dimensional CNF network was highlighted for the masterbatch-based composites holding 20 wt.% of PEG, corroborating the successfulness of our sustainable approach to disperse effectively CNF through melt blending techniques. Under thermo-mechanical loading, the rigid percolated CNF structure mastered the viscoelastic response of the plasticized composites, demonstrating the load-bearing capacity of well-entangled CNF in the glassy as well as in the rubbery state. This rapid and straightforward physical method is a suitable approach for preparing dried and concentrated melt-processable CNF masterbatches that can be adopted in conventional melt-processing methods at an industrial scale.
Abstract
In this study, cellulose nanofiber (CNF)-reinforced poly (lactic acid) (PLA) bionanocomposites were manufactured through industrially scalable equipments. The compatibility [...]
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Study of the influence of flame-retardant additives on the mechanical properties of epoxy-fiberglass and basalt composites
. N.Soriano, . A.Navarro, . B.López

Materiales Compuestos (2023). Vol. 03 - Comunicaciones Matcomp17 (2019), (Núm. 3 - Procesos de Fabricación II y Materiales Avanzados), 16

Abstract
One of the main problems of composites is fire resistance properties. New fire-retardant additives are able to modestly improve this problem, although mechanical properties can be depleted. For this reason, a large variety of phosphorus-based flame retardants have been studied for their flammability and their rheological and mechanical properties [1,2]. However, little research has been done on the mechanical and rheological properties of epoxy resins with non-halogenated flame retardants, and these must be at least mentioned in conjunction with the fire retardant characteristics, in order to acquire a global view of the compound. In this work, the correlation between the addition of non- halogenated flame retardants and the mechanical properties of composites (tensile properties, interlaminar shear, flexure) and different types of fiber (basalt and glass) has been researched.
Abstract
One of the main problems of composites is fire resistance properties. New fire-retardant additives are able to modestly improve this problem, although mechanical properties [...]
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Manufacturing and characterization of multimaterial components of titanium and composites of PEEK-carbon fibre
A. Pedreira, A. Collazo, E. Rodriguez

Materiales Compuestos (2023). Vol. 03 - Comunicaciones Matcomp17 (2019), (Núm. 3 - Procesos de Fabricación II y Materiales Avanzados), 15

Abstract
Nowadays, the aeronautical sector use composite materials reinforced with high performance fibers. In this field, the composites of thermoplastic matrix (TPCs) is reinforced with continuous carbon fibers wich combine both high strength and lightness thus offering a great potential to replacement, at least partially, the metal alloys. The thermoplastic matrix allows reducing manufacturing costs and minimizing recycling problems. The integration of TPCs sometimes forces to combine pieces which are very different in composition, forming a multimaterial. During the development of the research , the manufacturing and physical-mechanical characterization of the CF-PEEK composite material and the union of said material with titanium was carried out. Firstly, the characterization and optimization of the press forming process of the monolithic CF-PEEK has been developed. The characterization was carried out through DSC and TGA tests, mechanical tensile tests according to the standard UNE-EN 527-5 and microscopic analysis. Then, the CF-PEEK-Ti joints were made and evaluated.In order to improve the quality of the joints has been used Ti-6Al-4V with two surface treatments (shot blasting and laser texturing) and enrich the surface with PEEK film.The mechanical characterization was carried out through the SLJ (Single Lap Joint) test according to the standard ASTM D5868. The results have shown how the laser treatment improves the quality of the joint, achieving the highest efficiency by enriching the surface with PEEK film. The viability of multi-material joints has been demonstrated through direct production in the press.
Abstract
Nowadays, the aeronautical sector use composite materials reinforced with high performance fibers. In this field, the composites of thermoplastic matrix (TPCs) is reinforced [...]
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Development of ASA base composites for Large Format Additive Manufacturing
D. Moreno-Sancheza, V. Casal, S. Molina

Materiales Compuestos (2023). Vol. 03 - Comunicaciones Matcomp17 (2019), (Núm. 3 - Procesos de Fabricación II y Materiales Avanzados), 13

Abstract
Additive Manufacturing (AM) technologies are starting to be part of the naval industrial fabric, not only for creating prototypes, but also, for producing final parts. One of the most interesting AM technologies is material extrusion, mainly of melt thermoplastics, which are able to create 3D parts through a selective layer-by-layer deposition of polymeric melt-material beads. Concerning industrial area, there is a special interest in the new development of printers with various cubic meters in size, which allow to create parts for sectors such as naval accommodation, automotive, and wind energy. The development of new materials which satisfy the rheological, functional and mechanical requirements is fundamental for large format additive manufacturing technologies, in order to produce satisfactory parts. The latest published researches are focused on the development of thermoplastic materials reinforced with fibers (mainly carbon and glass) which lend the adequate properties for this end. Following this trend, this paper is focused on the development of new materials based on ASA (Acrylonitrile Styrene Acrylate), reinforced with carbon fibers, in order to be used in large format additive manufacturing devices for naval sector. Thanks to its intrinsic UV resistance property, this research might contribute to create parts for outdoor emplacement, extending its useful life in service.
Abstract
Additive Manufacturing (AM) technologies are starting to be part of the naval industrial fabric, not only for creating prototypes, but also, for producing final parts. One [...]
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ASSESSMENT AND FORECASTING OF STRESS RESISTANCE OF THE RUSSIAN BANKING SECTOR WITHIN THE FRAMEWORK OF RESTORING GROWTH UNDER CHANGED EXTERNAL AND INTERNAL CONDITIONS
S. Zubov, A. Vedev, M. Kovaleva

RUSSIAN PRESIDENTIAL ACADEMY OF NATIONAL ECONOMY AND PUBLIC ADMINISTRATION (2022). 1

Abstract
Relevance of the topic. In the conditions of increasing turbulence of the global business environment and instability of the financial system, rapid quantitative and qualitative transformations in the credit system under various financial, economic, social, political and other factors, banking supervision and regulation authorities, as well as the management of credit institutions are forced to constantly improve traditional approaches to assessing financial risks and develop new methods of early detection. In this regard, more and more attention is paid to a variety of stress testing methods that can determine the vulnerabilities of certain areas of banking and the banking system as a whole. The project was carried out as part of the research work carried out by the Laboratory for Structural Research of the Institute of Applied Economic Research of the Russian Presidential Academy of National Economy and Public Administration in 2021. Research method or methodology. The research work is based on the principle of consistency in the study of various economic phenomena, as well as the appropriate selection methods for the object of research. This use case assumes a variety of scientific and methodological tools: the use of methods of scientific abstraction, economic and statistical analysis, functional and structural analysis, a systematic approach, comparison methods, graphical and tabular techniques for visualizing statistical and other data, methods of expert analysis, methods of graphical modeling and others. Research results: an analysis was carried out to systematize approaches to stress testing, to develop criteria for ranking stress testing methods by areas of banking and by risk factors; stress testing models in the Russian banking system were optimized, tested and validated; prepared a scientific basis for the stability of the banking system in the event of extreme yet likely events.
Abstract
Relevance of the topic. In the conditions of increasing turbulence of the global business environment and instability of the financial system, rapid quantitative and qualitative [...]
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COMPARATIVE ANALYSIS OF METHODOLOGICAL APPROACHES OF CAPITAL INVESTMENTS IN NATIONAL ECONOMY
O. Izryadnova, M. Kovaleva

RUSSIAN PRESIDENTIAL ACADEMY OF NATIONAL ECONOMY AND PUBLIC ADMINISTRATION (2022). 2

Abstract
An investment policy focused on the implementation of national sustainable growth goals is based on an analysis of competitive advantages, problems and opportunities for attracting investment and mutual strengthening of public and private financing of ambitious development projects at the federal and regional levels. The reaction of investment and construction activities in the context of a pandemic to a simultaneous reduction in demand and supply was fundamentally different from the traditional scheme of financial and economic crises in the framework of long retrospective periods. A peculiarity of the crisis was the rather high synchronization of lockdown measures in the domestic and world markets, which had an extremely painful effect on the nature of capital flows. The functioning of the economy under the conditions of falling aggregate domestic demand, reduced incomes and growing budgetary constraints has actualized the study of the issues of mobilizing investment resources and creating conditions for supporting the structural transformation of the priority economic sectors in the context of increasing competitiveness and productivity. In this regard, the activities needed to clarify the regulatory framework for stimulating and supporting capital investments, public-private partnerships, protecting property rights, providing guarantees and distributing risks were updated. Overcoming the consequences of the pandemic and restoring sustainable growth is considered in the paradigm of changing the role and participation of the state, business, general public, and financial markets in mobilizing resources and financing national programs and investment projects with an increase in the scale and structural shifts in the distribution of investments in fixed assets.
Abstract
An investment policy focused on the implementation of national sustainable growth goals is based on an analysis of competitive advantages, problems and opportunities for attracting [...]
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Spectral and wavelet analysis in the wake of an airfoil with Gurney flap
P. Giacopinelli, A. Scarabino, F. Bacchi, J. Delnero

Rev. int. métodos numér. cálc. diseño ing. (2023). Vol. 39, (1), 7

Abstract
In this work we identify the coherent vortices in the leeward wake of an HQ 17 airfoil with a Gurney flap. This high-lift device consists of a small plate perpendicular to the airfoil, at or near the trailing edge, with a height H of the order from 1% to 4% of the chord. The overall effect is to produce a significant increase in lift, together with a relatively minor increase in airfoil drag. Its geometry generates vortex shedding of spatial scale H, which modulates the wake and thus influence the global configuration of the flow. A numerical study was performed with the commercial software ANSYS Fluent. Simultaneously, experiments were carried out in the wind tunnel of the Aeronautical Departmental Area from the Engineering School of the National University of La Plata. With a Dantec StreamLine hot-wire anemometer, records of the instantaneous horizontal and vertical velocity components in the airfoil wake were obtained. Both the experimental data and those obtained by numerical simulation were analyzed with the continuous wavelet transform technique, in order to identify and characterize the coherent vortices in the wake. Results show the shed vortices structure and the organization degree of this periodic shedding.
Abstract
In this work we identify the coherent vortices in the leeward wake of an HQ 17 airfoil with a Gurney flap. This high-lift device consists of a small plate perpendicular to [...]
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PROSPECTS FOR THE DEVELOPMENT OF PAYMENT AND PAYMENT SYSTEMS AND ASSESSMENT OF RISKS IN NEW EXTERNAL AND INTERNAL CONDITIONS
S. Zubov, A. Vedev, M. Kovaleva

RUSSIAN PRESIDENTIAL ACADEMY OF NATIONAL ECONOMY AND PUBLIC ADMINISTRATION (2022). 3

Abstract
The object of the research is the interconnections arising in the process of operation of Russian and foreign payment systems. The goal of the study is to conduct a comprehensive assessment of the risks faced by the settlement and payment systems operating in the context of the global recession, mounting sanctions against Russia, as well as the expected economic recovery and growth and the reorientation of production to new energy sources. Research methodology. In the course of the study, methods of scientific abstraction, economic and statistical analysis, functional and structural analysis, a systematic approach, a comparison method, graphical and tabular visualization techniques for statistical and other data, generalization and formalization were used. The project was carried out as part of the research work carried out by the Laboratory for Structural Research of the Institute of Applied Economic Research of the Russian Presidential Academy of National Economy and Public Administration in 2021. Research results: Description of the mechanisms of influence of organizational and technical factors on the state of the payment system and the implementation of cashless payments by commercial banks, Building a system of dependencies between the introduction of the latest payment systems and the development level of the financial market, as well as the main macroeconomic indicators, Analyzing traditional methods of risk assessment and management, proposing approaches to their improvement, Development of a methodology for backing up system-wide risk.
Abstract
The object of the research is the interconnections arising in the process of operation of Russian and foreign payment systems. The goal of the study is to conduct a comprehensive [...]
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Analysis of the impact of international standards for responsible business conduct on the financial sector in the world and in Russia: Formation of proposals for the development of regulation in Russia
I. Ermokhin, A. Levashenko

RUSSIAN PRESIDENTIAL ACADEMY OF NATIONAL ECONOMY AND PUBLIC ADMINISTRATION (2022). 4

Abstract
This paper analyzes the impact of international standards for responsible business conduct on the financial sector in the world and in Russia, and formulates proposals for the development of regulation in Russia. The relevance of the work lies in the need to analyze the impact of international standards for responsible business conduct on the financial sector in the world and in Russia, as well as to formulate proposals for the development of appropriate regulation in Russia. The study was conducted in 2021. The object of the study is the standards for responsible business conduct in the financial sector. The goal of the study is to analyze the impact of international standards for responsible business conduct on the financial sector in the world and in Russia, and to formulate proposals for the development of regulation in Russia. The following results were obtained: an analysis of the recommendations and standards of international organizations, including the OECD, related to responsible business conduct in the financial sector and their impact on access to financing for Russian companies; an analysis of the approaches of the OECD member countries, including the EU, France, Japan, Canada, and other countries, including China, to the regulation of responsible business conduct in the financial sector and the impact of the regulations adopted by these countries on the Russian companies’ access to financing; an analysis of the practices of legal regulation of responsible business conduct in the financial sector in Russia and their impact on access to finance for Russian companies; formulated proposals for the development of legal regulation of responsible business conduct in the financial sector in Russia in order to ensure access to financing for Russian companies. The practical significance of the work lies in the possibility of using its results for the development of regulatory documents aimed at the development of sustainable (green) financing in Russia, the formation of Russia's position on the OECD platform in relation to the developed standards of responsible financing.
Abstract
This paper analyzes the impact of international standards for responsible business conduct on the financial sector in the world and in Russia, and formulates proposals for [...]
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Impact analysis of automatic exchange of financial information in tax matters for business and natural persons
A. Koval, A. Levashenko

RUSSIAN PRESIDENTIAL ACADEMY OF NATIONAL ECONOMY AND PUBLIC ADMINISTRATION (2022). 5

Abstract
The paper analyzes the legal relationship connected with the development of instruments for automatic exchange of tax information, which are being developed at the OECD level. Subject of the research is analysis of the automatic exchange instruments and the results of its implementation in the practice of states. Relevance of the research is based on the expanding use of automatic exchange of tax information between countries and the issues arising in connection with its application, the emergence of new tax programs aimed at increasing tax transparency. The goal of the study was to identify the issues of automatic exchange and develop proposals for the development of tax exchange instruments. Research methodology was based on the use of methods of logical, system, formal legal and comparative legal analysis. The authors analyze existing instruments for the automatic exchange of information on foreign accounts, cross-country reports on the activities of multinational corporations, and instruments for exchanging information on the sellers’ activities on e-commerce platforms. The research lays the foundations for the development of multilateral instruments for automatic exchange of tax information at the OECD level. To minimize the risks of tax evasion and improve the efficiency of the automatic exchange of tax information, the study proposes steps aimed at increasing the efficiency of Russia's participation in the OECD automatic exchange instruments - CRS MCAA and CbC MCAA. Based on the research, the following findings were made. First, based on the analysis of the legislation of individual countries and the first Peer Review published by the OECD in December 2020, one may conclude that most jurisdictions have a satisfactory legal framework, while in some countries, including Russia, it requires significant improvements. Second, a number of problems remain in the implementation of the standard for automatic exchange of information in Russia, which are primarily associated with the lack of effective mechanisms of responsibility for violation of self-certification and with the retention of currency control requirements. The results of the research include proposals for the development of automatic exchange instruments both on the OECD platform and in Russia.
Abstract
The paper analyzes the legal relationship connected with the development of instruments for automatic exchange of tax information, which are being developed at the OECD level. [...]
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Specifics of taxation of profits upon payment of dividends
N. Milogolov, A. Berberov

RUSSIAN PRESIDENTIAL ACADEMY OF NATIONAL ECONOMY AND PUBLIC ADMINISTRATION (2022). 6

Abstract
Unlike other types of passive income, dividends are formed directly from the profit of a legal entity and thus, theoretically, can be taxed twice at the level of the company and the income recipient. Such disproportion in the conditions of economic activity creates several types of economic distortions, although tax conditions should not influence the economic agents’ decisions. The need to eliminate the disproportions determines the relevance of the topic, and the approach to its development determines the scientific novelty of this study. Thus, the goal of the work is to develop proposals for the harmonization of the taxation regime in the payment of dividends at the level of the company and its participants, including taking into account the problem of double taxation. In order to achieve this goal, the authors set the tasks that involve identifying the current features of the Russian tax legislation in terms of taxation on dividends, generalizing the relevant foreign experience, assessing the economic and fiscal consequences of different scenarios for reforming the current dividend taxation mechanism, and developing specific recommendations aimed at its improvement. The methodological basis of the study consisted of the following methods of scientific knowledge: historical and logical, statistical, induction and deduction, comparative analysis, synthesis, modeling, analogy, econometric, comparative legal. Based on the findings of the study, the authors made conclusions that economic distortions arising from double economic taxation when distributing profits in the form of dividends are characteristic of the Russian tax system; this is indicated, in particular, by the presence of 'debt bias' in the financing of Russian private companies, as well as the parallel existence of different taxation principles of capital gains and other income other than dividends (interest and licensing payments). The authors' recommendations present an interrelated system of measures aimed at improving the current model of dividend taxation, including a consideration of the new socio-economic challenges facing the Russian economy. The paper substantiates the expediency of transition to partial exemption of dividends from taxation at the individual level through harmonization of the dividends taxation regime with the system of capital gains taxation. In order to harmonize the rules of dividends taxation with the mechanism of controlled foreign companies, it is also justified to reduce the threshold of “substantial participation in the capital” to 25% while using a zero-profit tax rate for dividends received. The authors also justify the implementation of the “allowance for corporate equity” mechanism in the tax law, which would align the dividends and interest taxation principles and become an investment incentive to attract new equity capital for taxpayers. Prospects of research within the framework of this topic are related to the development of economic and legal signs indicating the payment of 'hidden dividends' by
Abstract
Unlike other types of passive income, dividends are formed directly from the profit of a legal entity and thus, theoretically, can be taxed twice at the level of the company [...]
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Development of the tax incentive mechanism in the field of information technology
A. Korytin, N. Kostrykina, E. Melkova

RUSSIAN PRESIDENTIAL ACADEMY OF NATIONAL ECONOMY AND PUBLIC ADMINISTRATION (2022). 7

Abstract
The relevance of the work is explained by the amendments to the tax legislation related to IT companies in Russia, the so-called “IT maneuver” adopted in 2021. Income tax and social insurance benefits were increased, while VAT exemption was reduced. In September 2021, the Government of the Russian Federation approved the second package of measures to support the IT industry, which includes several tax measures. The purpose of the second package is to increase the demand for domestic IT products, to accelerate digital transformation of the economy and social sphere, as well as to create favorable conditions for doing IT business in Russia. In this regard, the subject of our study is the mechanism of taxation and measures of tax policy for IT sector. The goal of the study is to analyze the effectiveness of tax incentives for the development and sale of products of IT industry with the aim of increasing the export of high value-added services, as well as assessing the impact of benefits on insurance premiums on the development of the information technology industry in Russia. The research method consists in analyzing domestic proposals for stimulating the IT industry as part of the “IT maneuver” and comparing them with foreign approaches to the development of the IT sector. To analyze the effectiveness of tax incentives, we use an empirical estimation of the dynamics of IT enterprises’ economic performance, which is then compared between two samples: 1) a sample of enterprises enjoying the IT benefit, and 2) a sample of enterprises that don’t have any benefits. The findings show that companies enjoying the IT benefit on social insurance payments significantly outpace companies that did not have the benefit in terms of economic growth. We draw a conclusion that the IT benefits encourage the development of the IT industry. The recommendations are to continue the expansion of incentives for the IT industry as part of the “IT maneuver”, taking into account various comments. In particular, it is necessary to develop additional measures to support small businesses in the IT sector, as well as to develop a mechanism against the use of IT benefits for tax optimization purposes only.
Abstract
The relevance of the work is explained by the amendments to the tax legislation related to IT companies in Russia, the so-called “IT maneuver” adopted in 2021. [...]
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ASSESSMENT OF THE EFFICIENCY OF EXPENDITURE ON HOUSING AND UTILITIES IN THE RUSSIAN FEDERATION
I. Sokolov, S. Belev, I. Arlashkin, G. Kozlyakov

RUSSIAN PRESIDENTIAL ACADEMY OF NATIONAL ECONOMY AND PUBLIC ADMINISTRATION (2022). 8

Abstract
Relevance. The issue of assessing the effectiveness of spending on housing and utility services in Russia remains underexplored. The volume of public funds allocated to the “Housing and Utility Services” sector nationwide has grown 60.2% in 2020 compared to 2016; compared to the total government spending, the increase is from 3.2% in 2016 to 3.7% in 2020. Relatively high government spending on housing and utility services in Russia is associated with numerous sectoral problems – primarily, severe deterioration of fixed assets. The utilities infrastructure continues to deteriorate in literally every region of the country. The goal of this study is to assess the effectiveness of the extended government’s spending on the housing and utility services in the Russian Federation, to develop recommendations for changing the spending structure and volume. The of the study is the budget spending of the extended government of the Russian Federation for housing and utility services. The general research methodology consists of critical analysis and reasoning, a hypothetico-deductive method, case studies, generalization analysis and extrapolation (interpolation) of results. The main findings of the study are as follows: approaches were identified and model tools developed to assess the impact of the volume and structure of government spending on the efficiency of housing and utility services; Russian and international practice of legislative regulation and financing of the housing and utility services sector was analyzed; based on the formulated hypotheses on the conditions and factors affecting the efficiency of the housing and utility services in Russia and abroad, econometric modeling was carried out and the results were interpreted to test the hypotheses; proposals and recommendations were formulated to change the structure and volume of government spending on the housing and utility services. The findings of the study can be used in the interests of the Accounts Chamber of the Russian Federation and the Ministry of Finance of Russia for the purpose of improving approaches to managing the costs of housing and utility services in the Russian Federation.
Abstract
Relevance. The issue of assessing the effectiveness of spending on housing and utility services in Russia remains underexplored. The volume of public funds allocated to the [...]
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Factor models of cryptocurrency profitability
E. Sinelnikova-Muryleva, M. Kuznetsova, K. Shilov

RUSSIAN PRESIDENTIAL ACADEMY OF NATIONAL ECONOMY AND PUBLIC ADMINISTRATION (2022). 9

Abstract
More than 12 years have passed since the debut of Bitcoin, the first cryptocurrency, but there is still no clear understanding of the essence of cryptocurrencies. At the same time, in recent years, interest in cryptocurrencies has continued to grow, and this financial instrument is becoming more and more attractive to individuals. Therefore, an issue of essence of cryptocurrencies is relevant. The main subject of the study is the profitability of cryptocurrencies. The main aim of this work is to identify the determinants of cryptocurrency returns. To achieve this goal, such tasks as the creation of factors reflecting the characteristics of the cryptocurrency market and the use of multifactor Fama-French models for the analysis of cryptocurrency returns were performed. Based on the collected daily data on capitalization, trading volumes and the price of more than 5,000 cryptocurrencies for the period from 01.04.2014 to 21.06.2021, standard factors based on capitalization indicators, trading volumes and the third momentum were built. The main estimation method is econometric modeling using the least squares method. The obtained results of an empirical study indicate a positive relationship between the profitability of groups of cryptocurrencies and the difference in the yields of the upper and lower 30% of cryptocurrencies according to the third moment. The difference in the yields of the lower and upper 30% of cryptocurrencies by market capitalization has a negative impact on the profitability of groups of cryptocurrencies. The main conclusion of the study is that before the beginning of high volatility period, cryptocurrencies could be considered as an asset for the diversification of market risk, but subsequently the cryptocurrency market began to move co-directionally to the stock market. The scientific novelty of the work stems from presenting an assessment of the impact of modeled factors on various groups (portfolios) of cryptocurrencies over certain periods of time. The study recommends to conduct further analysis of the profitability factors of cryptocurrencies on more homogeneous samples.
Abstract
More than 12 years have passed since the debut of Bitcoin, the first cryptocurrency, but there is still no clear understanding of the essence of cryptocurrencies. At the same [...]
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CONCEPTUAL FRAMEWORK AND THEORETICAL APPROACHES TO ANALYSIS OF TREND INFLATION
M. Kazakova

RUSSIAN PRESIDENTIAL ACADEMY OF NATIONAL ECONOMY AND PUBLIC ADMINISTRATION (2022). 10

Abstract
Today, trend inflation is one of the important components of monetary models, as well as an indicator of public confidence in the ongoing monetary policy. In addition, trend inflation is used when forecasting inflation over a long-term horizon. This explains the relevance of this work, which is aimed at illustrating the evolution of trend inflation concept (subject of the study), as well as determination of its place in macroeconomic models. A review of theoretical works analyzing the concept of trend inflation and its relationship with other macroeconomic indicators is aimed at achieving this goal. The study was conducted at the Center for the Study of Central Banking Problems as part of the RANEPA state assignment for 2021 using relevant academic literature and as the major source of information and such methods as descriptive, statistical, graphical analysis, a systematic approach, and comparative analysis. Analysis of trend inflation concept allows the authors to conclude that this indicator represents a long-term inflationary trend and is unobservable. In statistics, prices for food and raw materials characterized by high volatility, as well as the effects of changes in indirect taxes, are excluded from the indicator of general inflation in order to identify a long-term trend in the dynamics of the general price level. In addition, trend inflation concept is widely used in macroeconomic modeling. In the future, this review can serve as a starting point for an econometric estimation of trend inflation for the Russian economy; study of trend inflation factors in Russia; analysis of changes in the magnitude and volatility of this indicator over time; as well as formulation of recommendations for the Russian monetary authorities.
Abstract
Today, trend inflation is one of the important components of monetary models, as well as an indicator of public confidence in the ongoing monetary policy. In addition, trend [...]
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ASSESSMENT OF THE RIGIDITY OF INFORMATION FOR THE RUSSIAN ECONOMY
A. Bozhechkova, P. Trunin, A. Evseev, M. Chembulatova

RUSSIAN PRESIDENTIAL ACADEMY OF NATIONAL ECONOMY AND PUBLIC ADMINISTRATION (2022). 11

Abstract
The duration of monetary shocks in the economy is often explained not just by price rigidity, but also by the slow dissemination of information and the inertia of economic agents' expectations. Many methods for the information rigidity assessment are presented in the foreign scientific literature, but few such works exist in Russia. Therefore, the study of the information rigidity in the Russian economy is highly relevant. The subject of the study is information rigidity. The goal of this work is to study monetary policy in Russia, considering price rigidity and information rigidity. To achieve the goal of the study, we set the following objectives: a review of the models of imperfect information and methods of validating the hypotheses of these models’ compliance with the factual data based on a review of theoretical and empirical literature, data collection, validating the hypothesis of existence of imperfect information, obtaining quantitative estimates of information rigidity using the data for Russia. Research methods include statistical and econometric methods of time series analysis. We used data of consensus forecasts of professional analysts from Bloomberg and Interfax agencies, forecasts of the Ministry of Economic Development for the period from 2006 to 2020. Conclusions of the study: information rigidity was observed for forecasts of all macroeconomic indicators considered; the estimates of information rigidity vary for different macroeconomic variables; we also discovered a decrease in the degree of information rigidity during periods of increased instability in the economy. The results make it possible to explain the inertia in the response of macroeconomic variables to various shocks, including monetary policy shocks, and can be used in general equilibrium models.
Abstract
The duration of monetary shocks in the economy is often explained not just by price rigidity, but also by the slow dissemination of information and the inertia of economic [...]
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Development of methodology and technologies for managing the health of people employed at life support enterprises and a continuous cycle in pandemic conditions
S. Kovalev, E. Yashina, K. Lukichev, P. Turzin, A. Generalov, A. Evseev

RUSSIAN PRESIDENTIAL ACADEMY OF NATIONAL ECONOMY AND PUBLIC ADMINISTRATION (2022). 12

Abstract
The relevance of the study is due to the urgent need to develop a health management system for workers employed at life support and continuous cycle enterprises in the conditions of the new coronavirus infection (COVID-19). Subject of research: health management system for employees of life support and continuous cycle enterprises in the conditions of the pandemic. Objective: to develop approaches to human capital management at life-support and continuous cycle enterprises, excluding the possibility of downtime due to attrition (sick and quarantined staff) during pandemics and avoiding the risk of mass infection of workers with repeated waves of epidemics. Scientific novelty is determined by the development of new methods and technologies of the occupational health management system for workers at life support and continuous cycle enterprises in the conditions of pandemics. The study was conducted at RANEPA in 2021, using a set of analytical methods, questionnaires and programming. Methods: observation; surveys, system analysis, socio-economic analysis; comparative legal analysis; theory of multi-agent systems; formal analysis of historical phenomena; elements of the theory of expert systems, database creation. Results: Data from the analysis of the compliance of legal relations and international experience in managing workers’ health and the specifics of the organization of life support and continuous cycle enterprises during the COVID-19 pandemic; A model regulation on the health management service of life support and continuous cycle employees; A methodology for sociological research of organizational approaches by the subjects of the Russian Federation to ensure operation of continuous cycle enterprises in the conditions of increased emergency preparedness; Methodology of expert evaluation of investment projects in the field of workers’ health protection of workers and health management of workers at life support and continuous cycle enterprises during the actual pandemics; Methodological recommendations; Computer program "Interactive testing of knowledge in the field of healthy lifestyle, environmental well-being and prevention of coronavirus infection
Abstract
The relevance of the study is due to the urgent need to develop a health management system for workers employed at life support and continuous cycle enterprises in the conditions [...]
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Digital transformation in assessments and perceptions of university teachers
D. Rogozin, O. Solodovnikova, E. Vyugovskaya

RUSSIAN PRESIDENTIAL ACADEMY OF NATIONAL ECONOMY AND PUBLIC ADMINISTRATION (2022). 13

Abstract
This paper is based on the findings of the research work “Modern methodology for analyzing the process and effectiveness of distance education”, conducted by the team of the Field Research Center of the Institute for Social Analysis and Forecasting (RANEPA) in 2021. Since the beginning of the pandemic, our colleagues at the Field Research Center have conducted three waves of survey among university teachers dedicated to the urgent transition to distance learning and the ongoing digital transformation of universities. The results of the last third wave (April-May 2021) are presented in this paper. The hypotheses proposed at the start of the project have been confirmed: the respondents’ attitude to distance learning gets back to normal over time, and “hybrid” or mixed form of education begins to be perceived as a norm. However, these processes continue to take place in contrast to the stagnant problems in higher education. The overlapping of problems that have arisen due to the complexity of the higher education administration reform at its different stages creates a diversity of risks and opportunities in the process of digital transformation. The authors of this work would like not only to describe the current situation and the objective difficulties accompanying any changes, but present a map of the “bottlenecks” of modern distance learning, the “anxious moods” of certain social groups within the teaching community. The attention focused on these groups can relieve the stress of the transition to distance learning.
Abstract
This paper is based on the findings of the research work “Modern methodology for analyzing the process and effectiveness of distance education”, conducted by the [...]
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New trends in reproductive behaviour
A. Makarentseva, E. Seredkina

RUSSIAN PRESIDENTIAL ACADEMY OF NATIONAL ECONOMY AND PUBLIC ADMINISTRATION (2022). 14

Abstract
To develop an effective demographic and family policy, one has to understand the reproductive behavior features and attitudes of the younger generations. These features largely determine the current and future fertility levels. Firstly, this study aims to analyze the prospects of childlessness in Russia. Secondly, we analyze mating and reproductive behavior as well as the reproductive attitudes of the generation born in the 1990s. We reviewed Russian and foreign literature in the field of mating and reproductive behavior, analyzed statistical data and findings of the representative surveys “Person, Family, Society” (2020), “Generations and Gender Survey” (2011) performed by the RANEPA Institute for Social Analysis and Forecasting.
Abstract
To develop an effective demographic and family policy, one has to understand the reproductive behavior features and attitudes of the younger generations. These features largely [...]
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MONITORING AND ANALYSIS OF THE ACHIEVABILITY OF RUSSIA'S NATIONAL GOALS, CONSIDERING THE CONSEQUENCES OF THE COVID-19 PANDEMIC
Y. Pleskachev, Y. Ponomarev

RUSSIAN PRESIDENTIAL ACADEMY OF NATIONAL ECONOMY AND PUBLIC ADMINISTRATION (2022). 15

Abstract
Changes in all spheres of life due to the COVID-19 pandemic substantiate the relevance of this study. Its main objective was to assess the impact of the epidemic on the implementation of national projects and new national development goals. The subject of the research is theoretical and practical issues of building a system of strategic planning and monitoring of national goals, considering the consequences of the COVID-19 pandemic. The results show that updated national goals allowed setting the necessary accents, taking into account the impact of the pandemic; in particular, much more attention was paid to digital transformation. The main conclusion, as shown by a detailed examination, is that updating the goals and adjusting the passports of national projects made it possible to increase their interconnection with each other, and updating the Unified Plan for Achieving National Goals helped identify gaps in the set of measures aimed at achieving national goals. These gaps are intended to be filled by social and economic development initiatives that have been assessed in terms of their impact on the progress towards the national goals. Further areas of research include assessing the attainability of national goals depending on the success of updating the passports of national projects.
Abstract
Changes in all spheres of life due to the COVID-19 pandemic substantiate the relevance of this study. Its main objective was to assess the impact of the epidemic on the implementation [...]
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TECHNOLOGICAL ENTREPRENEURSHIP IN RUSSIAN UNIVERSITIES: FACTORS OF CONTAINMENT AND ACCELERATION
N. Kurakova, V. Zinov, E. Olga, L. Tsvetkova, F. Kurakov

RUSSIAN PRESIDENTIAL ACADEMY OF NATIONAL ECONOMY AND PUBLIC ADMINISTRATION (2022). 16

Abstract
Relevance. The role of universities in contemporary social and economic systems of various countries is undergoing significant changes and involves the actualization of approaches to defining the functions of educational organizations. At the same time, university startups are viewed as the most dynamic elements of regional economies, capable of creating export-oriented science-intensive products and new high-tech jobs. The transformation and development of regional entrepreneurial ecosystems using universities as a trigger for academic entrepreneurship involves the stimulation by the authorities of the constituent entities of the federation of the start-ups establishment process by universities in cooperation with local or global enterprises of the real sector of the economy. The objective of this study is to analyze the factors that stimulate academic technological entrepreneurship, as well as barriers that impede the implementation of business ideas of university employees and students, related, inter alia, to the commercialization of the results of intellectual activity (RIAs). The subject of study is the individual elements of entrepreneurial ecosystems and the degree of their influence on the acceleration of the technological development of the constituent entities of the Russian Federation. The study used general scientific analytical methods (case study, content analysis, comparative analysis). The sources of information were Russian and foreign scientific publications, official data of state authorities, the Bloomberg Terminal analytical system. Based on the results of the study, an overview of foreign practice of stimulating academic entrepreneurship is presented, key factors that determine the productivity of startup ecosystems of the world's leading universities and critical barriers that hinder the development of domestic technological entrepreneurial ecosystems are highlighted. The conducted study allows us to draw the following conclusions. In the constituent entities of the Russian Federation, it is not possible to find the entire set of basic factors that contribute to the involvement of RIAs created at the local universities into the regional economy, as well as the inclusion of startups founded by graduates or employees of universities in the horizontal network interaction. Critical barriers to the development of technological ecosystems include the following. There are no universities in the regions demonstrating global academic leadership (excellence). Academic entrepreneurship in regional universities of Russia is not institutionalized. Regional and national support for academic entrepreneurship does not include such an important element as creating a market for innovative university products at the regional, national and international levels. Universities have not created sufficient inter-university and intra-university venture and endowment funds, which causes a shortage of seed investments in technology projects developed on the basis of universities. Academic entrepreneurship is not facilitated by the structure of the existing body of young researchers, dominated by bachelors, while masters and graduate students only make up a small share of researchers. The low level of financial support for graduate students forces 90% of them to combine research activities with labor, and 80% of working graduate students find work outside the university, depriving the young researchers’ scientific and technological activities of a systemic nature. Most regional domestic universities still do not have an effective technology transfer system as a tool for harmonizing the interests of the authors of technical solutions and the university. The scientific novelty of the study is due to the proposed broad approach to the creation of legal conditions supporting deeper involvement of the constituent entities of the Russian Federation and business in the management of universities and in the implementation of development programs. The study substantiates the need to radically relax legal regulation, control and supervisory activities in relation to universities and to enshrine in law the right to risk for those ready to implement ambitious development projects. It is shown that direct support of promising teams at universities requires more autonomy for educational and scientific departments of the universities, including the right of separation, and targeted grant support to world-class teams with the right to move to another university, which would involve a radical revision of the role and functions of the rectors and Boards of Directors of the Universities. The authors emphasize the need to change approaches to the management of the property complex of universities; review the approaches to mergers and acquisitions of universities and scientific organizations in order to fundamentally transform the university management system and open it to beneficiaries. The recommendations for accelerating the institutional transformation of regional universities in Russia into entrepreneurial universities and the formation of university ecosystems include using a set of measures aimed at solving the problem of attracting seed funding for student startups; transforming the university management systems and opening them to beneficiaries; building the students’ educational paths depending on the needs of the founding student's startup; creating a network of university technology transfer centers; reforming the graduate school and creating a favorable environment for technological creativity.
Abstract
Relevance. The role of universities in contemporary social and economic systems of various countries is undergoing significant changes and involves the actualization of approaches [...]
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ANALYSIS OF COMPETITION DEVELOPMENT IN THE SPHERE OF ADDITIONAL EDUCATION
P. Gluhov, A. Popov

RUSSIAN PRESIDENTIAL ACADEMY OF NATIONAL ECONOMY AND PUBLIC ADMINISTRATION (2022). 17

Abstract
Today, the sphere of additional education for children is undergoing modernization processes, which, on the one hand, provide wider access to budget funds for private organizations and expand the individual capabilities of children, and on the other hand, are perceived by state organizations as restrictive measures aimed at withdrawing traditional funding. The processes of tightening the requirements and the development of supervision and control institutions in the originally liberal system of additional education for children are becoming noticeable. The purpose of the study is to identify qualitative trends in further development of the competitive environment and to propose optimal measures for neutralizing the negative effects hindering the development of the free market for educational services using empirical materials from the examination and analysis of the modernization progress in specific regions of the Russian Federation. The main methods include a full-scale assessment of the activities of organizational and managerial structures at the regional level with partial interviewing of the implementing subjects of the Target Model for the Development of Regional Systems of Continuing Education for Children, along with a high-quality examination of the documents adopted at the regional level. As a result of the study, it was possible to establish contradictions in the operations of educational systems at the municipal level, which indirectly result in unequal access to public funds for educational service providers, thereby limiting competition. As a result, a set of specific measures and changes in the regulatory framework is proposed to eliminate these contradictions. Further research prospects may be associated with a re-examination of the processes of modernization of regional systems of additional education for children, aimed at fixing established management models and assessing their effectiveness in terms of the private sector involvement, its legalization and institutional influence.
Abstract
Today, the sphere of additional education for children is undergoing modernization processes, which, on the one hand, provide wider access to budget funds for private organizations [...]
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Professional qualifications of teaching staff of general and vocational education and training
G. Golub, L. Fishman, V. Prudnikova

RUSSIAN PRESIDENTIAL ACADEMY OF NATIONAL ECONOMY AND PUBLIC ADMINISTRATION (2022). 18

Abstract
The object of the research is the professional qualifications of teaching staff in the Russian general and vocational education and training system in the context of qualification requests of types of professional activity, requirements of the current professional standards, and the targets of national educational development programs. The purpose of the research is to scientifically substantiate and test in practice the technology of modeling prospective labor functions and the corresponding professional qualifications of teachers of the general education system in the context of changing demands of the labor market and customers of the education industry. Main results and conclusions. The qualification requirements to teachers of the general and vocational education and training system, as well as corresponding professional qualifications and characteristics, are provided in the descriptors of the Sectoral Qualifications Framework in Education. The actual labor functions of a teacher in the vocational education and training system, a form master, a methodologist have been established, as well as a list of prospective labor functions of the teaching staff, which need to be institutionalized in the short term to ensure adequate response by educational organizations to changing requirements and demands to the processes and results of its work. The research has revealed the value put on the relevance of actual labor functions and the demand for promising labor functions of teaching staff by the employers in the industry. The ideas of employers in the field of education about the ways of building a professional career as a teacher are summarized. Contradictions are revealed between industry employers’ recognition of the diversification of pedagogical activity context in an educational organization and the stable professional and social stereotype of a "universal teacher". The hypothesis of hybridization of labor functions as a basic way of development of the sectoral qualification system in the field of education has been confirmed
Abstract
The object of the research is the professional qualifications of teaching staff in the Russian general and vocational education and training system in the context of qualification [...]
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Automated in situ consolidation process for pre-impregnated carbon fibers: a cyber physical approach
J. Rodrigues, F. Silva, J. Santos, J. S.Tavares, . L.Pina

Materiales Compuestos (2023). Vol. 03 - Comunicaciones Matcomp17 (2019), (Núm. 3 - Procesos de Fabricación II y Materiales Avanzados), 14

Abstract
The concept known as the fourth industrial revolution (Industry 4.0) has developed a wide field of study, such as the Internet of Things (IoT), Cyber-Physical Systems (CPS) and Information and Communication Technology (ICT), with the objective to achieve enhancing the processes performance of automated systems. This work focuses on the field of CPS for an in situ consolidation machine, which handles pre-impregnated, in this case unidirectional carbon fiber tapes with polyamide 6, in order to create composite laminates. The physical model involves an unwinding system that feeds the tape into a turning table through a pressing mechanism, which has a radiation heater before and refrigeration after the presser to guarantee the composite temperature. The objective is to model and simulate the heating process before, during and after the pressing mechanism to feed an optimization algorithm in order to calculate the optimal working parameters such as heaters power, heater positioning and process speed taking into account the temperatures of the tape, to avoid overheating and to improve process time. The results are processed, so that they can send and receive data constantly, to an optimization system to alter parameters, without making programing code changes and avoiding the need to stop the consolidation. The CPS can handle different classes of pre-impregnated composites, by learning during the consolidation process, in order to improve the overall result, without the need of fully or partially reprograming the code, which a main characteristic of CPS.
Abstract
The concept known as the fourth industrial revolution (Industry 4.0) has developed a wide field of study, such as the Internet of Things (IoT), Cyber-Physical Systems (CPS) [...]
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Development of flame retardant composites manufactured by ultraviolet cured pultrusion
I. Tena, I. Saenz-Dominguez, . J.Torre, L. Aretxabaleta, M. Sarrionandia, J. Aurrekoetxea

Materiales Compuestos (2023). Vol. 04 - Comunicaciones Matcomp19 (2020), (Núm. 2 - Procesos de Fabricación y Técnicas de Unión), 18

Abstract
Composites are on the strategic agendas of all manufacturers of transport sector (automobile, industrial vehicle, bus, train ...) and civil infrastructure. The development of new manufacturing processes such as out of die ultraviolet (UV) cured pultrusion can realise many concepts that are currently unfeasible. Therefore, it is essential that composites for automotive, transport or civil infraestructure present excellent fire resistance properties, particularly for structural applications. There are multiple strategies to improve the fire resistance of composites, but the peculiarities of the UV pultrusion process require the use of systems that allow the transmission of UV light through the material, and ensure a fast curing of the profile at the exit of the die to prevent expansion problems. Hence, different ignifugant strategies have been studied in this work: fillers or additives (alumina tri-hydrate, ATH), reactive compounds (ammonium polyphosphate, APP) and intumescent coatings. After analysing the different flame retardant strategies, it has been concluded that all the strategies improve the fire resistance capacity with respect to the base formulation, being the ATH and the intumescent coating the ones that present greater fireproof capacity.
Abstract
Composites are on the strategic agendas of all manufacturers of transport sector (automobile, industrial vehicle, bus, train ...) and civil infrastructure. The development [...]
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A BP neural network-based micro particle parameters calibration and an energy criterion for the application of strength reduction method in MatDEM to evaluate 3D slope stability
W. Jiang, Y. Tan, J. Yan, Y. Ouyang, Z. Fu, Q. Feng

Rev. int. métodos numér. cálc. diseño ing. (2023). Vol. 39, (1), 3

Abstract
To enhance the applicability of discrete element method in 3D slope stability analysis, a BP neural network-based micro parameter calibration method and an energy criterion are proposed by taking MatDEM as an example. Firstly, the relationship between the micro particle parameters and the shear strengths of particle aggregate are represented by using the BP neural network. And then the micro particle parameters are obtained for the given shear strengths by using a correction calibration. Next, the energy conversions are investigated for the stable and instable slope models in MatDEM. From a view of practical application, the abrupt in variation tendency and magnitude of the kinetic energy is selected for indicating the emergence of the limit equilibrium state of a slope. Finally, the effectiveness of the proposed improvements is testified by taking Baijiabao landslide as an example. Results verify that the calibration method established in this study is applicable to provide the micro particle parameters when the shear strength is constantly reduced, and the factor of safety determined by the kinetic energy criterion reflects the landslide stability at the global level.
Abstract
To enhance the applicability of discrete element method in 3D slope stability analysis, a BP neural network-based micro parameter calibration method and an energy criterion [...]
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Parallel computing for reducing time in security constrained optimal power flow analysis
D. Alvarez, D. Rodriguez, S. Rivera

Rev. int. métodos numér. cálc. diseño ing. (2023). Vol. 39, (1), 4

Abstract
This paper presents a novel approach for solving the security-constrained optimal power flow (SCOPF) optimization problem using parallel Computing. In this approach, switched shunt banks, generation power ramp, and demand response are considered in the SCOPF by maximizing the market surplus during regular operation and for a set of contingencies of branches and generators. The optimization problem is solved using the Nonlinear Interior Point Method. The contingency assessment is paralleled in multiple CPU cores to decrease the computation time. Additionally, the test systems used in ARPA-GO competition were used and compared with the ARPA benchmark results to assess the proposed algorithm. The numerical results show this method is suitable for fast SCOPF using paralleling Computing.
Abstract
This paper presents a novel approach for solving the security-constrained optimal power flow (SCOPF) optimization problem using parallel Computing. In this approach, switched [...]
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Passive periodic motion of an asymmetric spring loaded inverted pendulum hopping robot
Y. Ni, X. Meng

Rev. int. métodos numér. cálc. diseño ing. (2023). Vol. 39, (1), 2

Abstract
For improving the energy efficiency of hopping robot, an asymmetric spring loaded inverted pendulum hopping model with leg mass is considered. The period orbit problem of one-legged hopping robot is investigated. Firstly, the hybrid dynamic model is constructed. Then the passive hopping gaits are found using quasi-newton optimization method. Secondly, a PD controller is implemented to track the desired pitch trajectory of the body. Through applying control during stance phase, period orbits of the robot with offset body mass is obtained. Finally, the effect of the location of the leg mass and the body mass on hopping performances is investigated.
Abstract
For improving the energy efficiency of hopping robot, an asymmetric spring loaded inverted pendulum hopping model with leg mass is considered. The period orbit problem of [...]
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Stabilized reduced integration and sequentially linear analysis on the approximation of the non-linear behaviour of structures
H. Amezcua Rivera, A. Milián

Rev. int. métodos numér. cálc. diseño ing. (2023). Vol. 39, (2), 21

Abstract
In this paper, a computationally efficient strategy for the approximation of the non-linear behaviour of structures through the finite element method is proposed. This proposal is based on the execution of a set of linear analyses in which the strength of the elements where the damage occurs is sequentially degraded and, in addition, complemented with a stabilized reduced numerical integration scheme for solid finite elements. Thus, the stiffness matrix only contains information of one integration point and, consequently, the stresses are computed only at that point. Also, due to the stabilization, it is possible to use reduced integration not only in the elements where the damage is assumed to occur, but in all the elements, guaranteeing a greater reduction in the computational cost. In this paper, the strategy of sequentially linear analysis with stabilized reduced integration is applied to several validation as well as application examples in which the quality of the approximation and the computational efficiency achieved are discussed. Finally, some future developments for the strategy are proposed.
Abstract
In this paper, a computationally efficient strategy for the approximation of the non-linear behaviour of structures through the finite element method is proposed. This proposal [...]
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Optimal allocation of UPFC for congestion management using ANTLION algorithm
. D.Kesavan, . S.Padma, M. Kumar

Rev. int. métodos numér. cálc. diseño ing. (2023). Vol. 39, (2), 22

Abstract
To obtain an optimum power market the deregulation process is implemented for the entire electrical market and further classified as transmission and distribution units. Each firm focuses on delivering its best output which leads to congestion issues on transmission lines as there is in-adequate transmission capability to satisfy the load demand, and transmission congestion occurs. Transmission cable congestion results from a lack of coordination between the utilities that handle generating, transmission, and distribution leading to a generator failure, an abrupt increase in load demand, or the miscarriage of equipment, all of which can be fixed by FACTS devices. In this work, transmission line congestion is reduced using FACTS devices like UPFC and IPFC. The primary goal is to determine where FACTS devices should be placed. The main goal is to use the ANTLION optimization algorithm to locate the optimal position and size for FACTS devices. In an IEEE-14 bus system, UPFC and IPFC are individually connected and parameters are analyzed and formulated for better transmission among energy sectors.
Abstract
To obtain an optimum power market the deregulation process is implemented for the entire electrical market and further classified as transmission and distribution units. Each [...]
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Construction monitoring and finite element simulation of assembly support for large cantilever cover beam
C. Qu, H. Fang, Q. Feng

Rev. int. métodos numér. cálc. diseño ing. (2023). Vol. 39, (1), 1

Abstract
The study on the assembly support for the large cantilevered cover beam was carried out by conducting real-time monitoring on the assembly frames’ strain and displacement development processes in the actual project. Modeling of the support and numerical simulation for actual working conditions were presented. The monitoring data and analysis results show that the overall stress ratio of the support was less than 30%. And as the concrete structure being supported hardened, the support frame was unloaded. When the stress ratio was then reduced to less than 10%, it was the most appropriate time to remove the bracing frame. The maximum strain from the simulation did not exceed 66.26% of the theoretical maximum strain of the rod. The actual construction conditions and the spatial form of the support affected the force situation, resulting in the deviation from the theoretical maximum strain at certain phases. The analysis results and trends reflect the low utilisation rate of such framing rods. The results of the study can be used as a reference for the topology optimisation of assembled support frames for large cantilevered cover beams.
Abstract
The study on the assembly support for the large cantilevered cover beam was carried out by conducting real-time monitoring on the assembly [...]
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Application of the Discrete Elements Method for the simulation of a beam-column connection based on a self-centering system.
J. Álvarez, S. Gallegos, R. Cordero, A. Ramirez, F. Zarate, S. Diaz

Rev. int. métodos numér. cálc. diseño ing. (2023). Vol. 39, (2), 23

Abstract
At present, the beam-column connection system through a self-centering post-tensioned connection is currently an alternative to improve the seismic behavior in reinforced concrete buildings; by allowing its elements to have a linear behavior (no damage) in the face of displacements produced by seismic actions. This paper deals with the numerical modeling of the seismic behavior for a self-centering connection based on the Discrete Element Method (MED) is presented, with the aim of validating the hysterical response of the numerical model with an experimental test of the literature. The results demonstrated the horizontal distortions in the column, which are the product of the numerical simulation of the model subjected to a load that increases over time with 4 different stiffness coefficients. In addition, the hysteretic graph is presented as a result of the numerical simulation of the model, with an adequate stiffness coefficient and normal damping, subject to a cyclic load that is reversed as a function of time. The movement of the connection is controlled by the horizontal distortions of the column, achieving an approximate reproduction of the hysterical behavior expected in this type of connection. With the results shown, a simple bilinear hysteresis law is proposed, which allows its simplified use for its application in the modeling of reinforced concrete buildings with self-centering connections.
Abstract
At present, the beam-column connection system through a self-centering post-tensioned connection is currently an alternative to improve the seismic behavior in reinforced [...]
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Influência das superfícies sub-críticas no comprimento de reforços em estruturas de solos reforçados com geotêxteis ou geogrelhas
R. Puppi, J. Caron

Rev. int. métodos numér. cálc. diseño ing. (2023). Vol. 39, (2), 20

Abstract
Design of steep slopes and retaining walls, reinforced with geotextile or geogrids, requires internal stability checks usually referred to a critical failure surface, which determines the amount of reinforcement required. In determining the length of the reinforcement layers the position of the critical surface and also of the sub-critical surfaces must be considered. In relation to these, are verified the anchorage lengths required to ensure the pullout resistance of the reinforcements. This paper presents a study based on limit equilibrium analysis, with bi-linear failure surface, to determine the amount and length of the reinforcement layers required. The model allows replacing Jewell charts by algebraic equations and iterative calculation processes. The results obtained for the minimum length of reinforcements agree with good accuracy for effective friction angles greater than or equal to 30° and indicate that shorter lengths can be used for materials with lower effective friction angle. Expressions for the calculation of the anchorage length are also presented for the three possible cases: anchorage in a section under the projection, part under the projection and beyond the horizontal projection of the slope face. '''Palavras Chave –''' talude, solo reforçado, geotêxtil, geogrelha, superfície sub-crítica, comprimento de reforço.
Abstract
Design of steep slopes and retaining walls, reinforced with geotextile or geogrids, requires internal stability checks usually referred to a critical failure surface, which [...]
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Characterisation of mechanical behaviour of fibre reinforced thermoplastic composites subjected to off-axis compressive loading
Y. Ma, Y. Li, L. Liu

Rev. int. métodos numér. cálc. diseño ing. (2023). Vol. 39, (1), 5

Abstract
This paper presents an experimental and numerical investigation on the mechanisms of damage onset and evolution in unidirectional carbon fibre reinforced thermoplastic (CFRTP) composites subjected to off-axis compressive loadings. A test fixture was designed to prevent buckling, splitting and end collapsing of specimens during test. A series of compression tests were conducted with specimens of various off-axis angles. Different failure mechanisms and nonlinear stress-strain responses were observed and studied. The fracture angles of the tested specimens were evaluated and analysed according to Puck’s theory. The off-axis compression failure envelope based on LaRC05 and Hashin criteria was presented using finite element analysis and compared to experimental results. It is shown that the LaRC05 criterion can provide accurate predictions for matrix cracking failure mode of unidirectional thermoplastic composites controlled by compression-shear combined stresses.
Abstract
This paper presents an experimental and numerical investigation on the mechanisms of damage onset and evolution in unidirectional carbon fibre reinforced thermoplastic (CFRTP) [...]
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Análisis de las propiedades mecánicas de composites de fibra continua con electrónica impresa embebida
A. Pérez-Márquez*, J. Maudes, L. Bilbao, C. Vaquero, H. Villaverde, O. Adarraga, I. Bustero, I. Obieta, J. Gayoso

Materiales Compuestos (2023). Vol. 08 - COMUNICACIONES MATCOMP21 (2022) Y MATCOMP23 (2023), (Núm. 1 - Caracterización - Sostenibilidad y Reciclaje), 27

Abstract
Desde hace varios años surge la necesidad de desarrollar materiales compuestos multifuncionales, que además de las propiedades clásicas como alta resistencia y elevada rigidez, integren distintas funcionalidades como por ejemplo la capacidad de detectar cualquier deformación de la estructura o la integración de iluminación, en una tendencia hacia el aligeramiento de las estructuras. Sin embargo, en la mayoría de los casos, el hecho de embeber componentes físicos puede hacer que surjan aspectos negativos en las estructuras como la presencia de discontinuidades en la resina que son propensas a la delaminación o la iniciación de grietas alrededor del componente, disminuyendo sus propiedades estructurales. Las técnicas de fabricación, basadas en la impresión funcional para el desarrollo de circuitos y electrónica impresa como parte inherente de la estructura, son muy prometedoras y por ello, están consiguiendo una gran aceptación en el mercado. Este trabajo muestra el análisis de las propiedades mecánicas de composites de fibra continua con electrónica impresa sobre diferentes tejidos empleados en los propios procesos de fabricación como fibras de vidrio o sobre velos poliméricos fabricados a partir de la técnica de electrospinning. Los resultados obtenidos muestran que no existen diferencias relevantes en el comportamiento a tracción por el hecho de tener circuitos impresos e incluso con diferentes espesores de línea. Así mismo, el módulo de elasticidad no se ve afectado para el caso de los composites que embeban circuitos de iluminación basados en LEDs integrados sobre el velo. También se han analizado las impresiones sobre los distintos sustratos mediante microscopía y se ha medido el comportamiento de un sensor resistivo de temperatura impreso en el velo y embebido en composite, para el cual se ha conseguido una respuesta lineal con una sensibilidad de 4,9Ω/ºC.
Abstract
Desde hace varios años surge la necesidad de desarrollar materiales compuestos multifuncionales, que además de las propiedades clásicas como alta resistencia [...]
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A deep learning-based prognostic framework for aeroengine exhaust gas temperature margin
W. Fu, X. Tan, L. Ao, Y. Fu, P. Guo

Rev. int. métodos numér. cálc. diseño ing. (2023). Vol. 39, (2), 14

Abstract
The value of the gas-path parameter, exhaust gas temperature margin (EGTM), is the critical index for predicting aeroengine performance degradation. Accurate predictions help to improve engine maintenance, replacement schedules, and flight safety. The outside air temperature (OAT), altitude of the airport, the number of flight cycles, and water washing information were chosen as the sample input variables for the data-driven prognostic model for predicting the take-off EGTM of the on-wing engine. An attention-based deep learning framework was proposed for the aeroengine performance prediction model. Specifically, the multiscale convolutional neural network (CNN) structure is designed to initially learn sequential features from raw input data. Subsequently, the long short-term memory (LSTM) structure is employed to further extract the features processed by the multiscale CNN structure. Furthermore, the proposed attention mechanism is adopted to learn the influence of features and time steps, assigning different weights according to their importance. The actual operation data of the aeroengine are used to conduct experiments, where the experimental results verify the effectiveness of our proposed method in EGTM prediction.
Abstract
The value of the gas-path parameter, exhaust gas temperature margin (EGTM), is the critical index for predicting aeroengine performance degradation. Accurate predictions help [...]
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TOWARDS COPOLYMERISATION OF STEREOSPECIFIC PROPYLENE NANOCOMPOSITES WITH POLAR COMONOMERS BY IN SITU POLYMERISATION. OPTIMISING MECHANICAL PROPERTIES
K. Nuñez-Carrero, M. Asensio, J. Guerrero, M. Herrero, J. Pastor

Materiales Compuestos (2023). Vol. 07 - COMUNICACIONES MATCOMP21 (2022), (Núm. 3 - Materiales y Estructuras - Modelos Numéricos), 2

Abstract
The use of different stereospecific metallocene catalysts: isotactic (iPP, C2-symmetry) and syndiotactic (sPP, Cs-symmetry) has been investigated in order to improve the mechanical properties of polypropylene/nanoclay nanocomposites obtained by in-situ polymerisation. Stereoregular nanocomposites have been synthetized in the presence of polar comonomers (1-undecenol (R-OH) and acid-undecenoic (R-COOH) for improving the matrix-nanoclay chemical compatibility. An important study of variables: amount of nanoparticles used as co-catalyst support, type of catalyst, type and amount of comonomer have been studied in a full factorial design of experiments in order to identify the main factors that achieve a balance between the stiffness and toughness of the polypropylene nanocomposites. Important results were found from ANOVA (analysis of variance): the nanoclay has a greater influence on the syndiotactic configuration and, the amount of polar comonomer is the main factor in maximising mechanical properties, irrespective of stereospecificity of the polypropylene nanocomposites.
Abstract
The use of different stereospecific metallocene catalysts: isotactic (iPP, C2-symmetry) and syndiotactic (sPP, Cs-symmetry) has been investigated in order to improve the mechanical [...]
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AUTOMATIZATION IN NEW MANUFACTURING APPROACHES FOR BODY SHELL APPLICATIONS
A. Gutierrez, L. Mera, L. Carral, I. Coto, F. Ansedes, M. Plettig, S. Renner

Materiales Compuestos (2023). Vol. 07 - COMUNICACIONES MATCOMP21 (2022), (Núm. 3 - Materiales y Estructuras - Modelos Numéricos), 12

Abstract
The transport sector has exerted and continue to be the driving force for the development of new materials and lightweight solutions. The present study focuses on the work developed in a European project (CARBODIN https://carbodin.eu/) where one of the main objectives is to develop innovative and affordable solutions for advanced car body shells. Thus, contributing to the development of the next generation of passenger trains that will be lighter as well as more energy- and cost-efficient. Composite materials appear to be one of the most promising candidates to attain these ambitious targets. Therefore, new strategies to achieve greater automation are presented as novel manufacturing routes and offer a cost-effective industrial solution. This study has allowed the integration of unconventional technologies, such as AFP, within conventional production systems, such as VIP, which is the key to developing sustainable units, overcoming the common difficulties associated with processing and achieving the modularity of the manufacturing process and the reduction of the weight of the final rail structure. For this reason, a comparison of the manufacture of both monolithic composites and sandwich structures have been obtained through the VIP process, manufactured in an automated and manual way. Several automated approaches have been studied, with the choice of the robotized lay up of bindered dry fibers. An out of autoclave manufacturing was assisted through different monitoring technologies such as resin arrival sensors and thermography in order to ensure high quality components.
Abstract
The transport sector has exerted and continue to be the driving force for the development of new materials and lightweight solutions. The present study focuses on the work [...]
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Contribution of auxetic core structures on the radial impact behaviour of 3D printed continuous fibre reinforced polyamid profiles
U. Morales*, A. Esnaola, I. Sukia, L. Aretxabaleta, J. Aurrekoetxea

Materiales Compuestos (2023). Vol. 08 - COMUNICACIONES MATCOMP21 (2022) Y MATCOMP23 (2023), (Núm. 1 - Caracterización - Sostenibilidad y Reciclaje), 31

Abstract
The present study investigates the enhanced energy absorption capabilities in the radial direction of structures through the combination of continuous glass fiber reinforced polyamide hollow sections (cGF/PA) and complex cellular cores manufactured by 3D printing cFF (continuous Fibre Fabrication). For this purpose, two types of auxetic structures based on conventional reentrant structure designs (hexagonal and octagonal) have been characterised. Likewise, the energy absorption capacity (SEA) of the filled profiles has been analysed and compared with the capability of the hollow profiles. Falling weight impact tests have been carried out for the dynamic characterization of the profiles and the effect of concentric fibers and the auxetic core on filled profiles has been analysed. On the one hand, it has been identified that the octagonal re-entrant structure (RSH) presents a higher impact performance, reaching a SEA value of 8.5 kJ/kg. On the other hand, it has been found a substantial improvement in the absorption capability of the filled profiles (17.7 kJ/kg) compared to the capability of the hollow profiles (2.5 kJ/kg). The SEA values achieved are promising, as they are 18% higher than the values found in literature.
Abstract
The present study investigates the enhanced energy absorption capabilities in the radial direction of structures through the combination of continuous glass fiber reinforced [...]
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Novel Manufacturing Approaches For Car Body Shell Applications Based On Sandwich Structures
L. Carral, L. Mera, A. Gutierrez, P. Rodriguez, X. Pérez, M. Pletting, S. Renner

Materiales Compuestos (2023). Vol. 07 - COMUNICACIONES MATCOMP21 (2022), (Núm. 3 - Materiales y Estructuras - Modelos Numéricos), 3

Abstract
The transport sector has exerted and continue to be the driving force for the development of new materials and lightweigth solutions. The present study focuses on the work developed in a recently completed European project (CARBODIN https://carbodin.eu/) where one of the main objectives is to develop innovative and affordable solutions for advanced car body shells. Composite materials appear to be one of the most promising candidates to attain these ambitious targets. However, to overcome the cost barrier as well as meet additional railway requirements, new strategies such as process integration and novel manufacturing routes are needed, which will offer a cost-effective industrial solution. The case study corresponds to a C-Groove insert used as an anchoring point to hang passenger seats off the car body side walls, to fix Interior Panels or luggage racks. To improve this design, a trendsetting design was developed to integrate composite C-Grooves to Composite sidewalls. This work will display the details of such design as well as the optimal manufacturing strategy to achieve it. An out of autoclave (OoA) manufacturing process was assisted through different monitoring technologies such as resin arrival sensors and thermography to ensure high quality components. Additionally, a multi-material approach based on 3D printed technologies has been tackled. A thorough analysis of the joint has been performed and different integration approaches have been explored by designing co-cured and co-bonded manufacturing stages. Finally, several demonstrators have been made and tested to define the most promising integration approach and scaling up yet again to a larger demonstrator.
Abstract
The transport sector has exerted and continue to be the driving force for the development of new materials and lightweigth solutions. The present study focuses on the work [...]
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Development of more sustainable PUR formulations for structural applications
O. Echeverria Altuna, O. Ollo, I. Harismendy, A. Eceiza

Materiales Compuestos (2023). Vol. 07 - COMUNICACIONES MATCOMP21 (2022), (Núm. 3 - Materiales y Estructuras - Modelos Numéricos), 9

Abstract
The industry decarbonization has become in a fundamental challenge for the industries such as automotive or wind power. In this way, the structural components lightening is one of the principal issues for material manufacturers. For this objective, the composites are a competitive alternative, due to their unique relation between their strength and weight. Among the different structural composite part fabrication processes, liquid composite moulding (LCM) is one of the most interesting, due to its efficiency in terms of costs, time and energy consumption. In this sense, resins with fast cure and low viscosity are gaining attention, among them polyurethanes are of particular interest. This family of polymers is characterized by its great versatility, among them high-performance thermosetting polyurethanes (PUR). The advantages offered by PUR-based technology are great fatigue resistance, low viscosity and fast cure. However, the commonly used PUR’s for structural applications have some environmentally drawbacks, such as their components petrochemical origin and their low recyclability. For this reason, the aim of this work was the development of a more sustainable PUR formulation with the required mechanical properties for structural applications and suitable processability for LCM processes. Because of that, this work has focused on the analysis, synthesis and characterization of new PUR formulations and also the manufacturing process simulation and optimization.
Abstract
The industry decarbonization has become in a fundamental challenge for the industries such as automotive or wind power. In this way, the structural components lightening is [...]
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Micromechanical modeling of the non-linear behaviour of angle-ply laminates under different plane-stress states
S. Horta Muñoz, M. Serna Moreno, D. Garoz, R. Sevenois, W. Paepegem

Materiales Compuestos (2023). Vol. 07 - COMUNICACIONES MATCOMP21 (2022), (Núm. 3 - Materiales y Estructuras - Modelos Numéricos), 5

Abstract
The non-linear behaviour ocurring in symmetrical angle-ply laminates formed by unidirectional layers of carbon fiber reinforced polymeric matrix (CFRP), known as pseudo-ductility, has been previously studied numerically and experimentally under different uniaxial, biaxial and bending loads. This phenomenon is associated with different mechanisms which affect the mechanical behaviour of the material: large permanent strains, fiber reorientation and matrix cracking. The present study is based on a microscale approach through simulations based on the Finite Element Method (FEM), with the aim of predicting the homogenized response of these laminates subjected to multiaxial in-plane. The micromechanical model is based on a Representative Volume Element (RVE) where Periodic Boundary Conditions (PBC) are applied, together with a non-linear material model of the matrix and a cohesive interface between fibre and matrix. In addition, the implementation of the model is updated to be able to reproduce any plane stress state in a [±45]S laminate, without the need to add other meso- or macroscale models.
Abstract
The non-linear behaviour ocurring in symmetrical angle-ply laminates formed by unidirectional layers of carbon fiber reinforced polymeric matrix (CFRP), known as pseudo-ductility, [...]
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Procedimiento de extrapolación de leyes cohesivas de uniones adhesivas en modo I y II: validación numérica
A. Arrese, U. Garitaonaindia, I. Adarraga, F. Mujika

Materiales Compuestos (2023). Vol. 08 - COMUNICACIONES MATCOMP21 (2022) Y MATCOMP23 (2023), (Núm. 1 - Caracterización - Sostenibilidad y Reciclaje), 32

Abstract
En este trabajo se presenta y valida numéricamente un novedoso procedimiento de extrapolación para predecir las leyes cohesivas de uniones adhesivas en modo I y II. En primer lugar, partiendo de los métodos de reducción de datos basados en la variación de la flexibilidad recientemente propuestos para extraer las leyes cohesivas, se definen nuevas expresiones factorizadas con respecto a la carga aplicada y a los espesores de adhesivo y adherente de la flexibilidad (C0i), la Integral–J (J0i) y el desplazamiento de la punta de la grieta (Δ0i) para cada modo de fractura. Suponiendo que todos los efectos asociados al daño se incluyen en la longitud de grieta equivalente, y de acuerdo con las expresiones polinómicas de J0i, C0i y Δ0i con respecto a la misma, se obtienen relaciones invariantes entre J0i-C0i y Δ0i-C0i para cualquier relación de espesores adhesivo-adherente de un sistema material y configuración de ensayo determinados, tanto en modo I como en modo II. Por último, se presenta un procedimiento de extrapolación basado en las curvas calibradas J0i-C0i y Δ0i-C0i, que permite estimar las leyes cohesivas para un amplio rango de relación de espesores adhesivo-adherente de un sistema material dado procesando únicamente la curva carga-desplazamiento del ensayo.
Abstract
En este trabajo se presenta y valida numéricamente un novedoso procedimiento de extrapolación para predecir las leyes cohesivas de uniones adhesivas en modo [...]
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Estudio de procesabilidad de composite CF-LMPAEK reciclado: inyección vs impresión 3D
C. Martín-Pérez, D. Rosario, N. González-Castro, R. Travieso-Puente, E. Rodríguez-Senín

Materiales Compuestos (2023). Vol. 08 - COMUNICACIONES MATCOMP21 (2022) Y MATCOMP23 (2023), (Núm. 1 - Caracterización - Sostenibilidad y Reciclaje), 26

Abstract
El proyecto ECO-CLIP se basa en una combinación de actividades de innovación orientadas a lograr piezas estructurales más ligeras a partir de los residuos de fábrica de TPC´s (Thermoplastic Composites), para la próxima generación de demostradores de fuselaje de aviación, que se lleva a cabo como parte de Clean Sky 2. En el proyecto se ha desarrollado un material polimérico compuesto de LMPAEK reforzado con un 40% en peso de fibra de carbono corta para la producción de Brackets. Con el fin de seleccionar la tecnología más ventajosa para la fabricación de estos, se ha llevado a cabo la comparativa de un método de fabricación convencional, como es la inyección, con una tecnología emergente, como es el FGF (Fused Granulated Fabrication). Para su comparativa se han llevado a cabo estudios de longitud y distribución de fibra, caracterización térmica y ensayos mecánicos, tanto para las probetas de inyección como en FGF. En esta última tecnología, además se ha llevado a cabo un estudio de parametrización de diámetros de boquillas con el fin de obtener la influencia que tiene en la adhesión entre capas, la longitud de la fibra, la microestructura de la pieza y la calidad final de las piezas. Gracias a estos resultados se ha podido establecer una relación entre la naturaleza del refuerzo, las propiedades térmicas y los parámetros de fabricación, con las propiedades mecánicas en pieza final.
Abstract
El proyecto ECO-CLIP se basa en una combinación de actividades de innovación orientadas a lograr piezas estructurales más ligeras a partir de los residuos [...]
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AEROPLAS – Desarrollo de componentes para la industria aeronáutica mediante tecnologías de bajo coste
. , S. Pintos

Materiales Compuestos (2023). Vol. 07 - COMUNICACIONES MATCOMP21 (2022), (Núm. 3 - Materiales y Estructuras - Modelos Numéricos), 4

Abstract
El futuro del sector aeronáutico está orientado a fabricar estructuras y componentes más ligeros y rentables, empleando materiales y tecnologías más ecológicos que permitan reducir costes, peso y consumo de combustible con ciclos de fabricación más cortos, a la vez que se aumenta la eficiencia energética en la fabricación. En este contexto surge el proyecto AEROPLAS, con el objetivo de contribuir al proceso de fabricación avanzada de composites termoplásticos utilizando tecnologías de bajo coste para la industria aeronáutica. En el presente estudio se abarca la sustitución de piezas aeronáuticas fabricadas actualmente en composite termoestable por composite termoplástico, en dos componentes reales: panel de cubierta y puerta de acceso del carenado ventral del A350, empleando dos materiales de distinta calidad: un semipreg de LM-PAEK/CF (TenCate Cetex® TC1225) y un prepreg de PC/CF (ePreg245CHT/PC40). Mediante diseño y cálculo, se han obtenido los apilados y espesores de pieza necesarios para cubrir los requerimientos estructurales de ambos componentes, a partir de los datos obtenidos de la caracterización de los materiales de partida. Se han estudiado y comparado dos procesos de fabricación para la obtención de las nuevas piezas, seleccionando el termoformado y la estampación como los más prometedores. Por último, se ha llevado a cabo la caracterización de las piezas obtenidas mediante ensayos no destructivos (inspección visual, verificación por ultrasonidos, inspección dimensional mediante laser tracker) y destructivos (tracción en sentido plano [AITM1-0066], resistencia al aplastamiento [AITM1-0009], resistencia a tracción del laminado [AITM1-0007], resistencia a tracción de unión atornillada [AITM1-0067]).
Abstract
El futuro del sector aeronáutico está orientado a fabricar estructuras y componentes más ligeros y rentables, empleando materiales y tecnologías [...]
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Descomposición en modos en ensayos de fractura interlaminar y de uniones adhesivas con brazos de grieta asimétricos
F. Mujika

Materiales Compuestos (2023). Vol. 08 - COMUNICACIONES MATCOMP21 (2022) Y MATCOMP23 (2023), (Núm. 1 - Caracterización - Sostenibilidad y Reciclaje), 28

Abstract
Las pruebas de flexión con entalla final y viga en doble voladizo se diseñaron para caracterizar la fractura interlaminar de materiales compuestos en modos puros I y II. En ambos casos, los especímenes tienen una longitud de fisura inicial en la mitad del espesor. En el caso de especímenes bimaterial, si la grieta está ubicada en el medio del espesor, el modo mixto podría existir, debido a la asimetría material. El objetivo del presente estudio es proponer relaciones geométricas para obtener condiciones de modo puro cuando se ensayan especímenes bimateriales en configuraciones DCB y ENF.
Abstract
Las pruebas de flexión con entalla final y viga en doble voladizo se diseñaron para caracterizar la fractura interlaminar de materiales compuestos en modos puros [...]
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Design of toroidal Pressure Vessels for Hydrogen Trains using FEM and Artificial intelligence Techniques
A. CORZ, D. Patiño-Perez, M. Lopez

Materiales Compuestos (2023). Vol. 07 - COMUNICACIONES MATCOMP21 (2022), (Núm. 3 - Materiales y Estructuras - Modelos Numéricos), 6

Abstract
One of the main objectives in the design of HSS (Hydrogen Storage Systems) containers for trains is to be able to store hydrogen as a compressed gas at a pressure of 70MPa and to consider the stresses and fatigue cycles due to loading and unloading (type IV tanks). ); In addition, failure analysis by means of finite elements for the generation of toroidal models will be included in the study. Given that another aspect of the design is to be able to rationalize the price of HSS tanks, by optimizing the geometry and thickness of CFRP (Carbon Fiber Reinforced Polymer), which generally represents 50% of the total price, and which It can be done through one of Ansys' own optimization methods that provides a reliable result at a high computational cost for each new container pattern that is modelled; Through the use of artificial intelligence techniques, a model will be created that has the capacity to learn from the characteristics of each new container model, but at a low computational cost and with a high level of reliability; the prediction methodology will be based on a regression and classification model through supervised learning and deep learning techniques through the use of artificial neural networks implemented on Keras, reliable results will be obtained that will speed up virtual tests in the design of a resistant container, light and with a high storage capacity.
Abstract
One of the main objectives in the design of HSS (Hydrogen Storage Systems) containers for trains is to be able to store hydrogen as a compressed gas at a pressure of 70MPa [...]
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Comparative study of the mechanical properties of carbon fiber composite materials for the development of aeronautical structural elements
J. Sánchez Garrucho, M. Jiménez, N. Muñoz, P. Luna, K. Muñoz, M. Iglesias, L. Rubio, F. Martín

Materiales Compuestos (2023). Vol. 07 - COMUNICACIONES MATCOMP21 (2022), (Núm. 3 - Materiales y Estructuras - Modelos Numéricos), 8

Abstract
Carbon fibre reinforced polymer composite material structures continue to be, despite the tremendous technological maturity achieved in recent decades, one of the most promising options to address the challenges of the aeronautical industry with respect to behaviour in the face of efforts such as improvements, regarding weight or costs. Ongoing demands to address major societal challenges, promote industrial leadership in Europe, and address aviation decarbonisation for the purpose of protecting the environment drive the demand for more optimal materials designed to improve these aspects. The previous tasks carried out to complete the test campaign will be described, showing its plan and design, details of preparation, assembly of the specimens and the execution of the tests. The philosophy proposed by Airbus (ADS) is presented with the consolidation of admissible design against alterations of the material that could realize its evolution or arise in the manufacturer's batches. Observing changes in the material, leading to the improvement of its mechanical and handling characteristics, a comparison has been made by Airbus with the one used previously for the determination of admissible design. It is intended to incorporate assessments of effects associated with the process of its industrialization. Once the results and analyzes are available, the normalized results of the conclusions would be presented. The activity carried out is included within the CERES project (Advanced Rear End Structural test program), belonging to the Clean Sky 2 Joint Undertaking European research aeronautical program.
Abstract
Carbon fibre reinforced polymer composite material structures continue to be, despite the tremendous technological maturity achieved in recent decades, one of the [...]
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Paneles fabricados mediante curado UV de prepregs fuera de autoclave reforzados con perfiles de pultrusión UV
I. Eguino, G. Goenaga, A. Arruti, I. Saenz-Dominguez, I. Tena, F. Vallejo, M. Sarrionandia, J. Aurrekoetxea

Materiales Compuestos (2023). Vol. 08 - COMUNICACIONES MATCOMP21 (2022) Y MATCOMP23 (2023), (Núm. 1 - Caracterización - Sostenibilidad y Reciclaje), 29

Abstract
En el presente trabajo se ha demostrado el potencial de la tecnología de curado UV cuando se aplica en los materiales compuestos reforzados con fibra de vidrio. Se han comparado dos vías de fabricación de paneles; la fabricación por separado de ambos elementos y su posterior adhesivado, y la integración directa de los perfiles en el curado UV de las pieles. Los resultados de ensayos interlaminares demuestran que la resistencia de la unión prepreg/perfil es equiparable a la de la unión prepreg/prepreg. Consecuentemente, los prototipos obtenidos con ambas estrategias muestran prestaciones mecánicas similares, tanto en rigidez como en resistencia a la flexión. Por último, la baja temperatura con la que se da el curado UV de la piel permite utilizar núcleos hidrosolubles fabricados mediante impresión 3D que facilitan las operaciones de laminado y la compactación.
Abstract
En el presente trabajo se ha demostrado el potencial de la tecnología de curado UV cuando se aplica en los materiales compuestos reforzados con fibra de vidrio. Se [...]
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VITRIMER RESIN DEVELOPMENT FOR AERONAUTICAL APPLICATION
T. Blanco, E. Puerto*, N. Markaide*, A. Luzuriaga, A. Salaberria

Materiales Compuestos (2023). Vol. 07 - COMUNICACIONES MATCOMP21 (2022), (Núm. 3 - Materiales y Estructuras - Modelos Numéricos), 1

Abstract
Due to the environmental challenges the aeronautical industry is facing, the development of recyclable aeronautical chemistries have recently raised huge interest. Within this context, different alternatives are being considered with the aim of obtaining new resins with current thermoset resin chemical and mechanical performance, while showing reprocessing, repairability and recyclability capabilities, like thermoplastics. New vitrimer resins, based on dynamic covalent chemistry, become a very attractive alternative to combine the main advantages of aeronautical thermosets (processing conditions / temperature, means, properties…) and thermoplastics (recycling, welding…). Therefore, they can be the solution to overcome the current limitations of thermoset epoxy resin, which is widely used in composite airframe. This project, framed within the national funding PTA (Plan Tecnológico Aeronáutico), was focused on the preliminary development of aeronautical vitrimer resin for composite airframe. It was proposed as continuation of the EU Horizon 2020 consortium AIRPOXY led by CIDETEC, where a first generation of aeronautical RTM vitrimer was developed and characterised, while a second generation vitrimer development was only started. This chemistry is based on the use of dynamic aromatic disulfides as hardener. In the first 2021 project phase, following key activities were performed: Definition of targets or reference values for aeronautical infusion resin Second generation of infusion vitrimer: development completion and characterization Flat CFRP laminates with second generation vitrimer: production and thermoforming trials. Next steps of the project in 2022 and 2023, will be focused on developing, evaluating and demonstrating an aeronautical prepreg based on vitrimer resin with higher Tg in line with current aeronautical resin values.
Abstract
Due to the environmental challenges the aeronautical industry is facing, the development of recyclable aeronautical chemistries have recently raised huge interest. Within [...]
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Simulation of damage phenomena in metamaterials
R. Montero-Mayoral, V. González-Albuixech, M. Sanz-Gómez, V. Yanes

Rev. int. métodos numér. cálc. diseño ing. (2023). Vol. 39, (2), 13

Abstract
Metamaterials are generated from an interrelated set of cells and can present a macroscopic behaviour that differs from the one that characterizes its basic constituents. Modelling the influence that the damage and fracture of the elemental constituents have in the macroscopic properties of the metamaterial is relevant for its mechanical analysis. Altering the resistant behaviour of the elements (changing their longitudinal elastic modulus), it is possible to approximate the effect of the damage in the complete structure. It is considered as valid the substitution of the damage and plastic deformation phenomena by intermediate states contained in the linear elastic deformation regime. Each state is characterized by the elastic module of the element, whose geometry remains unmodified. In an iterative process, when the induced stress in the elements is greater than the one stablished as the limit, they progress through the different states, diminishing their elastic modulus until they are considered as fractured and are eliminated from the structure. Mass effects are ignored, and a stress-free structure is implemented to calculate each iteration. A simple algorithm is presented to simulate the effect of damage in metamaterial structures, applicable to any finite element software.
Abstract
Metamaterials are generated from an interrelated set of cells and can present a macroscopic behaviour that differs from the one that characterizes its basic constituents. [...]
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Curing distortion simulation applied to thermoset CFRP components
J. González Cantero, S. Van-der-Veen, P. Bourbon

Materiales Compuestos (2023). Vol. 07 - COMUNICACIONES MATCOMP21 (2022), (Núm. 3 - Materiales y Estructuras - Modelos Numéricos), 7

Abstract
Manufacturing Process Simulation (MPS) is on the rise nowadays to predict manufacturing defects and deviations, especially during the design phases where it allows the engineers to take earlier decisions and helps to reduce the manufacturing trials to go for a Right at First Time philosophy. MPS, focusing on composite materials, lies on the physical and chemical behavior of the material during the different stages of manufacturing (e.g. forming, infusion, curing, etc.) to predict defects, distortion and residual-stresses in the final component. Airbus Group has developed simulation tools and defined procedures to obtain an accurate prediction of the shape of a thermoset CFRP component. These simulations are run by using a high-fidelity description of the material considering its chemical and physical behavior during the full curing cycle. Curing distortion shape is obtained by simulating the cure cycle on the properly meshed component. This procedure is shown on an industrial component, where the final deformation is validated with experimental measurements and it is linked with additional manufacturing process simulations. The experience gained shows that future research should focus on linking up simulations of successive manufacturing steps: start by simulating the lay-up process or the forming, then carry across predicted fields such as real local fiber angle and volume fraction into the curing distortion prediction and so on up to high-fidelity simulation of the assembly of the airframe. A particular point of interest is the viscoelastic behavior in post-curing, as well as the analysis of the stress relaxation in ply overlaps during curing.
Abstract
Manufacturing Process Simulation (MPS) is on the rise nowadays to predict manufacturing defects and deviations, especially during the design phases where it allows the engineers [...]
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Pruebas de fuego virtuales de paneles compuestos termoplásticos
F. MILLAN, M. FROVEL, F. CABRERIZO, M. TORRE, . F.LOPEZ, D. BENITO, R. TEJERINA, . S.LOPEZ(‡).

Materiales Compuestos (2023). Vol. 08 - COMUNICACIONES MATCOMP21 (2022) Y MATCOMP23 (2023), (Núm. 1 - Caracterización - Sostenibilidad y Reciclaje), 30

Abstract
Este artículo describe el desarrollo de una metodología de simulación FEM para predecir el comportamiento de un panel compuesto con matriz termoplástica y fibras de carbono en pruebas de fuego. El panel tiene un soporte de metal en su centro a cuál se aplica simultáneamente una carga monotónica mecánica al inicio del ensayo de fuego. La herramienta tiene como objetivo capturar los fenómenos más relevantes involucrados en este complejo problema y centrarse en predecir el tiempo de desprendimiento del soporte bajo la carga aplicada, que es el resultado más relevante de dicha prueba de fuego. En el problema, muchos diferentes fenómenos físicos están involucrados. Para considerar los más relevantes, se ha seleccionado un FEM termomecánico acoplado y, dentro de él, un análisis de fluencia transitoria. Las partes más relevantes de la simulación son los supuestos del modelo térmico, el modelo constitutivo mecánico del material, la dependencia de la temperatura de las propiedades térmicas y mecánicas y la selección de un criterio de fallo consistente. Durante el desarrollo de la metodología de simulación se han tomado precauciones para identificar un conjunto de parámetros que conforman los ajustes disponibles. Seleccionando un conjunto de valores para estos parámetros, se puede simular un caso de prueba concreto. Manteniendo los valores de estos parámetros sin cambios, la metodología puede predecir casos similares en lugar de probar estos casos físicamente en ensayos de fuego. Este artículo se centra en el desarrollo de herramientas de simulación. Por el momento solo se han realizado tareas iniciales de correlación y validación. Se espera completar y mejorar esta investigación en el futuro aumentando la validez de la simulación, p.ej. incluyendo cargas de tracción y/o ángulos/distancias de llama. En el documento también se proporciona una idea de las posibles simplificaciones y mejoras de las herramientas.
Abstract
Este artículo describe el desarrollo de una metodología de simulación FEM para predecir el comportamiento de un panel compuesto con matriz termoplástica [...]
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Numerical modeling of railway ballast using the discrete element method
J. Irazábal González

Universitat Politècnica de Catalunya (2015).

Abstract
The development of high-speed train lines has increased during the last twenty years, leading to more demanding loads in railway infrastructures. For these reasons, a discrete element model of granular material was carried out using 3D spherical particles with a rolling resistance, in order to consider non-sphericity of ballast stones. Other discrete element model representing granular materials as sphere aggregates (sphere clusters) has been also implemented. Current work presents the methodology followed to develop the discrete element model able to calculate railway ballast interaction. Interaction between discrete and finite elements is another key point of the calculations that is addressed. This document displays some results evaluating the influence of material parameters and geometric representation in the simulation of railway ballast and presents some laboratory tests calculated with the numerical application developed.
Abstract
The development of high-speed train lines has increased during the last twenty years, leading to more demanding loads in railway infrastructures. For these reasons, a discrete [...]
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