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• A cut finite element method for the solution of the full-potential equation with an embedded wake

  M. Davari, R. Rossi, P. Dadvand, I. López, R. Wüchner

  Computational Mechanics (2019). Vol. 63 (5), pp. 821-833 (Preprint)

  
  

  Abstract

  Potential flow solvers represent an appealing alternative for the simulation of non-viscous subsonic flows. In order to deliver accurate results, such techniques require prescribing explicitly the so called Kutta condition, as well as adding a special treatment on the “wake” of the body. The wake is traditionally modelled by introducing a gap in the CFD mesh, which requires an often laborious meshing work. The novelty of the proposed work is to embed the wake within the CFD domain. The approach has obvious advantages in the context of aeroelastic optimization, where the position of the wake may change due to evolutionary steps of the geometry. This work presents a simple, yet effective, method for the imposition of the embedded wake boundary condition. The presented method preserves the possibility of employing iterative techniques in the solution of the linear problems which stem out of the discretization. Validation and verification of the solver are performed for a NACA 0012 airfoil. 

  Abstract
  Potential flow solvers represent an appealing alternative for the simulation of non-viscous subsonic flows. In order to deliver accurate results, such techniques require prescribing [...]

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• A robust algorithm for implicit description of immersed geometries within a background mesh

  D. Baumgärtner, J. Wolf, R. Rossi, P. Dadvand, R. Wüchner

  Advanced modeling and simularion in engineering sciences (2018). Vol. 5 (1), pp. 1-40

  
  

  Abstract

  The paper presents a robust algorithm, which allows to implicitly describe and track immersed geometries within a background mesh. The background mesh is assumed to be unstructured and discretized by tetrahedrons. The contained geometry is assumed to be given as triangulated surface. Within the background mesh, the immersed geometry is described implicitly using a discontinuous distance function based on a level-set approach. This distance function allows to consider both, “double-sided” geometries like membrane or shell structures, and “single-sided” objects for which an enclosed volume is univocally defined. For the second case, the discontinuous distance function is complemented by a continuous signed distance function, whereas ray casting is applied to identify the closed volume regions. Furthermore, adaptive mesh refinement is employed to provide the necessary resolution of the background mesh. The proposed algorithm can handle arbitrarily complicated geometries, possibly containing modeling errors (i.e., gaps, overlaps or a non-unique orientation of surface normals). Another important advantage of the algorithm is the embarrassingly parallel nature of its operations. This characteristic allows for a straightforward parallelization using MPI. All developments were implemented within the open source framework “KratosMultiphysics” and are available under the BSD license. The capabilities of the implementation are demonstrated with various application examples involving practice-oriented geometries. The results finally show, that the algorithm is able to describe most complicated geometries within a background mesh, whereas the approximation quality may be directly controlled by mesh refinement.

  Abstract
  The paper presents a robust algorithm, which allows to implicitly describe and track immersed geometries within a background mesh. The background mesh is assumed to be unstructured [...]

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• Three embedded techniques for finite element heat flow problem with embedded discontinuities

  M. Davari, R. Rossi, P. Dadvand

  Computational Mechanics (2017). Vol. 59 (6), pp. 1003-1030 (Preprint)

  
  

  Abstract

  The present paper explores the solution of a heat conduction problem considering discontinuities embedded within the mesh and aligned at arbitrary angles with respect to the mesh edges. Three alternative approaches are proposed as solutions to the problem. The difference between these approaches compared to alternatives, such as the eXtended Finite Element Method (X-FEM), is that the current proposal attempts to preserve the global matrix graph in order to improve performance. The first two alternatives comprise an enrichment of the Finite Element (FE) space obtained through the addition of some new local degrees of freedom to allow capturing discontinuities within the element. The new degrees of freedom are statically condensed prior to assembly, so that the graph of the final system is not changed. The third approach is based on the use of modified FE-shape functions that substitute the standard ones on the cut elements. The imposition of both Neumann and Dirichlet boundary conditions is considered at the embedded interface. The results of all the proposed methods are then compared with a reference solution obtained using the standard FE on a mesh containing the actual discontinuity.

  Abstract
  The present paper explores the solution of a heat conduction problem considering discontinuities embedded within the mesh and aligned at arbitrary angles with respect to the [...]

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• Open tools for electromagnetic simulation programs

  J. Mora, R. Otín, P. Dadvand, E. Escolano, M. Pasenau, E. Oñate

  COMPEL: the international journal for computation and mathematics in electrical and electronic engineering (2006). Vol. 25 (3), pp. 551-564

  
  

  Abstract

  Purpose The aim of the paper is to propose three computer tools to create electromagnetic simulation programs: GiD, Kratos and EMANT. Design/methodology/approach The paper presents a review of numerical methods for solving electromagnetic problems and presentation of the main features of GiD, Kratos and EMANT. Findings The paper provides information about three computer tools to create electromagnetic simulation packages: GiD (geometrical modeling, data input, visualisation of results), Kratos (C++ library) and EMANT (finite element software for solving Maxwell equations). Research limitations/implications The proposed platforms are in development and future work should be done to validate the codes for expecific problems and to provide extensive manual and tutorial information. Practical implications The tools could be easily learnt by different user profiles: from end‐users interested in simulation programs to developers of simulation packages. Originality/value This paper offers an integrated vision of open and easily customisable tools for the demands of different users profiles.    

  Abstract
  Purpose The aim of the paper is to propose three computer tools to create electromagnetic simulation programs: GiD, Kratos and EMANT. Design/methodology/approach The [...]

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• Disaster risk reduction: a decision-making support tool based on the morphological analysis

  N. Lantada, M. Carreño, N. Jaramillo

  International Journal of Disaster Risk Reduction (2020). Vol. 42, pp. 101342:1-101342:17

  
  

  Abstract

  Risk management due to natural hazards is a multidimensional and complex problem since it requires the knowledge and experience of several disciplines. The effectiveness of risk management can be analyzed, inviting to the action through weakness identification of the urban area. This article proposes a methodology based on the morphological analysis to support the decision-making on disaster risk management, taking as a starting point the results of a holistic evaluation of the seismic risk. The results of the holistic evaluation of risk are achieved aggravating the physical risk using the contextual conditions, such as the socio-economic fragility and the lack of resilience. In consequence, the risk mitigation can be performed through the reduction of the potential damage and consequences involved; and the improvement of social conditions. The proposed methodology allows prioritizing the risk reduction strategies according to i) performance level of component indicators involved into the Disaster Risk Management index, DRMi; ii) physical risk factors dependent from the potential damages, and iii) aggravating factors involved in the aggravating coefficient. Moreover, it involves 35 strategies to reduce the physical risk and the aggravating social conditions of the urban area. The proposed methodology has been applied to the city of Mérida (Venezuela), located within an area of high seismic activity. The performance level of the indicators involved in the DRMi was evaluated by a survey to local experts. As a result, eleven strategies have been identified to reduce the potential damage and to improve the social conditions of this city

  Abstract
  Risk management due to natural hazards is a multidimensional and complex problem since it requires the knowledge and experience of several disciplines. The effectiveness of [...]

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• Methodologies and tools of risk management: Hurricane Risk index (HRi)

  M. Hernández, M. Carreño, L. Castillo

  International Journal of Disaster Risk Reduction (2018). Vol. 31, pp. 926-937

  
  

  Abstract

  Mexico is recognized worldwide for the extension of its coastlines and its tourist exploitation. Quintana Roo is one of the Mexican states, which has a shoreline of approximately 800 km, known as the Mexican Caribbean. The hurricanes that form in the Atlantic Ocean are the main natural hazard to which this region is exposed. In this article, hurricane risk is evaluated for coastal cities through the definition of a system of indicators. Based on this indicators system, the Hurricane Risk Index (HRi) is calculated. This system allows the construction of vulnerability indices for different dimensions: physical, environmental, social, economic, cultural and institutional. The obtained results can contribute to the definition of public prevention policies and actions to reduce the levels of vulnerability and increase the resilience of these communities. This indicators model is applied to two coastal cities of the Mexican Caribbean; Mahahual, obtaining an HRi of 82.13%, and Chetumal obtaining an HRi of 69.31%, corresponding to the impact of Hurricane Dean in 2007. The proposed indicators system can be replicated for different hazards

  Abstract
  Mexico is recognized worldwide for the extension of its coastlines and its tourist exploitation. Quintana Roo is one of the Mexican states, which has a shoreline of approximately [...]

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• Latin American and Caribbean earthquakes in the GEM’s Earthquake Consequences Database (GEMECD)

  O. Cardona, M. Ordaz, M. Salgado, A. Barbat, M. Carreño

  Natural hazards (2018). Vol. 93 (Supplement 1), pp. 113-125

  
  

  Abstract

  Among the activities developed under the framework of the Global Earthquake Model, the development of a global consequences database was included. This was defined with the objective of serving as public repository of damages and losses, occurred on different types of elements because of a selected list of earthquakes with epicentres at varying locations around the globe, but also to be used as a benchmark for the development of vulnerability models that capture specific characteristics of the building typologies in each country. The online earthquakes consequences’ database has information on 71 events where 16 of them occurred in the Latin America and the Caribbean Region. A complete and comprehensive review and data gathering process were developed for these selected earthquakes accounting for different aspects and dimensions that were considered of interest, besides the physical damage, such as casualties, socio-economic implications, damages and disruptions in critical facilities and infrastructures, together with the occurrence of secondary events triggered by the ground shaking such as landslides and tsunamis. When possible, the damage and casualties were geo-located using a standardized approach and included in the database. The contributions of the Latin America and Caribbean Region to the database were at the same time a challenge and an opportunity to collect, review, put together and standardize, up to a certain point, damage data of previous earthquakes additionally of being a step forward in the field of open data.

  Abstract
  Among the activities developed under the framework of the Global Earthquake Model, the development of a global consequences database was included. This was defined with the [...]

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• Evaluation of social context integrated into the study of seismic risk for urban areas

  N. Jaramillo, M. Carreño, N. Lantada

  International Journal of Disaster Risk Reduction (2016). Vol. 17, pp. 185-198 (Preprint)

  
  

  Abstract

  Usually the seismic risk evaluation involves only the estimation of the expected physical damage, casualties or economic losses. This article corresponds to a holistic approach for seismic risk assessment which involves the evaluation of the social fragility and the lack of resilience. The complementary evaluation of social context aspects such as the distribution of the population, the absence of economic and social development, deficiencies in institutional management, and lack of capacity for response and recovery; is useful in order to have seismic risk evaluation suitable to support a decision making processes for risk reduction. The proposed methodology allows a standardized assessment of the social fragility and lack of resilience, by means of an aggravating coefficient of which summarizes the characteristics of the social context using fuzzy sets and Analytic Hierarchy Process (AHP). The selection of 20 social indicators is based on the indicators used by urban observatories of United Nations and other social researchers. These indicators are classified according to social item they describe, in six categories. Applying the determination level analysis, thirteen prevailing social indicators are selected. The proposed methodology has been applied in the cities of Merida (Venezuela) and Barcelona (Spain)

  Abstract
  Usually the seismic risk evaluation involves only the estimation of the expected physical damage, casualties or economic losses. This article corresponds to a holistic approach [...]

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• Probabilistic assessment of seismic risk of Barcelona, Spain, using the CAPRA platform

  M. Marulanda, M. Carreño, O. Cardona, A. Barbat

  Bulletin of the polutechnic institute of jassy (2012). Vol. LVIII (2), pp. 9-25

  
  

  Abstract

  The Comprehensive Approach for Probabilistic Risk Assessment (CAPRA), is a robust methodology for modeling risk which allows identifying the most important aspects of catastrophes. CAPRA performs the evaluation of losses of the exposed elements using probabilistic metrics, such as the loss exceedance curve, the expected annual loss and the probable maximum loss, which are useful for multi-hazard risk analysis. The outcomes obtained with such a technical-scientific methodology are oriented to facilitate decision-making. They allow designing risk transfer instruments, evaluating the cost–benefit ratio, developing risk mitigation strategies and loss scenarios for emergency response, etc. The CAPRA platform is described in this paper by using as a testbed the city of Barcelona, Spain. Nevertheless, the results included for this urban area have not only a high scientific interest but also a practical one, because they are useful in taking risk reduction decision by the Municipality

  Abstract
  The Comprehensive Approach for Probabilistic Risk Assessment (CAPRA), is a robust methodology for modeling risk which allows identifying the most important aspects of catastrophes. [...]

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• Comportamiento sismico de los edificios de Lorca

  M. Carreño, N. Lantada, J. Padilla, J. Valcárcel, A. Barbat, X. Suriñach

  Física de la Tierra (2012). Vol. 24, pp. 289-314

  
  

  Abstract

  Después de ocurrido el terremoto de Lorca, el 11 de mayo de 2011, el Institut Geològic de Catalunya (IGC), la Universidad Politécnica de Cataluña (UPC) y la Asociación Española de Ingeniería Sísmica (AEIS) organizaron, junto con las asociaciones de ingeniería sísmica francesa (AFPS) y portuguesa (SPES), una visita técnica con el objeto de realizar observaciones que permitieran calibrar, verificar y validar los métodos utilizados en las evaluaciones de riesgo sísmico en zonas urbanas. Este artículo resume los aspectos más destacados en cuanto a la observación de la vulnerabilidad de edificios de vivienda, así como de edificios de especial importancia como son hospitales y escuelas. After the earthquake of Lorca, May 11, 2011, the Geological Institute of Catalonia (IGC), the Technical University of Catalonia (UPC) and the Spanish Association for Earthquake Engineering (AEIS) organized a technical visit in order to compile information that allow to calibrate, to verify and to validate the methods used in seismic risk assessments in urban areas. This article summarizes the highlights regarding the vulnerability of residential buildings and buildings of special importance such as hospitals and schools

  Abstract
  Después de ocurrido el terremoto de Lorca, el 11 de mayo de 2011, el Institut Geològic de Catalunya (IGC), la Universidad Politécnica de Cataluña [...]

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