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• A Refined Quadrilateral Element for Analysis of Plate Bending

  R. Clough, C. Felippa

  (1968). A Refined Quadrilateral Element for Analysis of Plate Bending

  
  

  Abstract

  The formulation of a fully compatible general quadrilateral plate bending element is described. The element is assembled from four partially constrained linear curvature compatible triangles, arranged so that no mid-side nodes occur on the external edges of the quadrilateral; thus, the resulting element has only 12 degrees of freedom. Also described is a simple shear distortion mechanism which may be incorporated into the element without changing its basic structure. Results are presented for static analyses with and without shear distortion, and for plate vibration and plate buckling studies, all performed with this quadrilateral element. It is concluded that this is the most efficient general bending element yet devised.

  Abstract
  The formulation of a fully compatible general quadrilateral plate bending element is described. The element is assembled from four partially constrained linear curvature compatible [...]

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• Model Based Partitioned Simulation of Coupled Systems

  C. Felippa, K. Park

  (1970). Computational Aspects of Structural Acoustics and Vibration. CISM International Centre for Mechanical Sciences, vol 505. Springer, Vienna.

  
  

  Abstract

  This tutorial paper is extracted from a set of graduate lectures on the time-domain simulation of structural dynamics and coupled systems. This material has also served as a basis for a CISM lecture series on FSI. For the treatment of coupled systems, emphasis is placed on partitioned analysis procedures. Although the subject emerged in the present form over 20 years ago, the time-consuming study of competing formulations and implementations can be streamlined through the use of various tools such as reduction to model equations, and the help of computer algebra systems.

  Abstract
  This tutorial paper is extracted from a set of graduate lectures on the time-domain simulation of structural dynamics and coupled systems. This material has also served as [...]

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• A Classification of Interface Treatments for FSI

  C. Felippa, K. Park, M. Ross

  (1970). Fluid Structure Interaction II. Lecture Notes in Computational Science and Engineering, vol 73. Springer, Berlin, Heidelberg.

  
  

  Abstract

  This paper proposes a taxonomy of methods for the treatment of the fluid-structure interface in FSI coupled problems. The top-level classification is based on the presence or absence of Additional Interface Variables (AIV) as well as their type. Associated prototype methods: Direct Force Motion Transfer (DFMT), Mortar and Localized Lagrange Multipliers (LLM) are defined. These are later studied in more detail using a specific FSI benchmark problem used in Ross’ 2006 thesis. Desirable attributes of the interfacing methods are stated and commented upon.    

  Abstract
  This paper proposes a taxonomy of methods for the treatment of the fluid-structure interface in FSI coupled problems. The top-level classification is based on the presence [...]

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• An alphanumeric finite element mesh plotter

  C. Felippa

  International Journal for Numerical Methods in Engineering (1972). Vol. 5 (2), pp. 217-236

  
  

  Abstract

  A FORTRAN subroutine name MESHPL is described. This routine generates an alphanumeric image of an arbitrary two-dimensional finite element mesh on the line printer. This plotting technique can be used for fast on-line display of nodal points, elements, boundary conditions and loads during the input data preprocessing stage of a finite element analysis.

  Abstract
  A FORTRAN subroutine name MESHPL is described. This routine generates an alphanumeric image of an arbitrary two-dimensional finite element mesh on the line printer. This plotting [...]

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• Solution of linear equations with skyline-stored symmetric matrix

  C. Felippa

  Computers and Structures (1975). Vol. 5 (1), pp. 13-29

  
  

  Abstract

  Fortran IV subroutines for the in-core solution of linear algebraic systems with a sparse, symmetric, skyline-stored coefficient matrix are presented. Such systems arise in a variety of applications, notably the numerical discretization of conservative physical systems by finite differences or finite element techniques. The routines can be used for processing constrained systems without need for prearranging equations. The application to ‘superelement’ condensation of large-scale systems is discussed.

  Abstract
  Fortran IV subroutines for the in-core solution of linear algebraic systems with a sparse, symmetric, skyline-stored coefficient matrix are presented. Such systems arise in [...]

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• Procedures for computer analysis of large nonlinear structural systems

  C. Felippa

  (1977). Proceedings of the International Symposium Held at the University of Manitoba, Winnipeg, Manitoba, pp. 60-101

  
  

  Abstract

  The paper surveys computerized solution techniques for treating large algebraic systems arising in the discrete-element analysis of nonlinear structural systems. Following a brief review of a general-purpose program organization, the principal features of the nonlinear analysis process are discussed. Solution techniques are categorized into four major groups, and the most important algorithms pertaining to each group are described. It is stressed that no particular method can be considered to be uniformly superior to all others if a wide range of practical applications is considered. A problem-adaptive combination of various procedures is therefore recommended for implementation in general-purpose codes.

  Abstract
  The paper surveys computerized solution techniques for treating large algebraic systems arising in the discrete-element analysis of nonlinear structural systems. Following [...]

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• Optimization of finite element grids by direct energy search

  C. Felippa

  Applied Mathematical Modelling (1976). Vol. 1 (2), pp. 93-96

  
  

  Abstract

  One of the possible approaches to the reduction of computational costs in finite element analysis is the selection of ‘optimal grids’, which produce the ‘best’ answers, in the sense of minimizing a discretization error measure, for a fixed level of computational effort. The grid optimization problem is studied in the case of grids of similar topology having a fixed number of degrees of freedom per node. A general formulation based on weighted-residual error measures is specialized to field problems associated with a positive-definite energy functional, the minimization of which, with respect to variable node locations, is adopted as a grid optimality criterion. The problem is then embedded in the framework of the general nonlinear programming problem, and desirable computational features of candidate search algorithms are described.  

  Abstract
  One of the possible approaches to the reduction of computational costs in finite element analysis is the selection of ‘optimal grids’, which produce the [...]

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• Error analysis of penalty function techniques for constraint definition in linear algebraic systems

  C. Felippa

  International Journal for Numerical Methods in Engineering (1977). Vol. 11 (4), pp. 709-728

  
  

  Abstract

  The penalty function approach has been recently formalized as a general technique for adjoining constraint conditions to algebraic equation systems resulting from variational discretization of boundary value problems by finite difference or finite element techniques. This paper studies the numerical behaviour of the penalty function method for the special case of individual equation constraints imposed on a symmetric system of linear algebraic equations. Constraint representation and computational roundoff error components are distinguished and asymptotically characterized in terms of the penalty function weight coefficients. On the basis of this study, practical rules for the automatic assignment of values to those coefficients within the linear equation solver are proposed. Numerical problems encountered in the case of more general constraints are briefly discussed, and procedures for circumventing such difficulties are suggested.

  Abstract
  The penalty function approach has been recently formalized as a general technique for adjoining constraint conditions to algebraic equation systems resulting from variational [...]

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• Stabilization of staggered solution procedures for fluid--structure interaction analysis

  C. Felippa, K. Park, J. DeRuntz

  (1977). Computational Methods for Fluid-Structure Interactions Problems, AMD, Vol. 26

  
  

  Abstract

  This paper addresses direct time integration techniques for the transient response analysis of coupled fluid-structure problems treated by a class of surface interaction approximations. Efficient solution of the resulting equations of motion can be achieved by a modular computer implementation in which separate fluid and structure analyzers are interfaced through extrapolation of the coupling terms. Such an implementation is herein called a staggered solution strategy. The conventional realization of this strategy is handicapped, however, by severe temporal stepsize limitations. Several stabilized formulations are introduced, which circumvent such limitations and achieve unconditional stability for certain extrapolators.

  Abstract
  This paper addresses direct time integration techniques for the transient response analysis of coupled fluid-structure problems treated by a class of surface interaction approximations. [...]

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• Estática y Resistencia de Materiales

  S. Oller, L. Nallim

  bookscimne (2020). 1

  
  

  Abstract

  Este libro está dirigido a la formación de estudiantes de ingeniería, arquitectura y también a ingenieros y arquitectos como base de consulta para el ejercicio de la profesión. Presenta un enfoque de la Resistencia de Materiales enriquecido con nuevos conceptos y con ejemplos resueltos mediante herramientas informáticas, ayudando así a establecer una metodología de trabajo simple, reduciendo los tiempos de solución de los problemas y permitiendo una mejor asimilación de los conceptos fundamentales. El libro es fruto de la extensa experiencia de los autores dedicada a la enseñanza de esta temática y ha sido pensado para satisfacer la necesidad de conocimiento de los estudiantes de ingeniería y arquitectura. Con este objetivo se ha escrito este texto que permite el aprendizaje de las bases para el análisis de estructuras en general y piezas de máquinas. Este libro, además de los temas clásicos de la Resistencia de Materiales, incursiona sobre las bases del tratamiento de piezas de paredes delgadas, de materiales compuestos laminados y reforzados en general, como así también de hormigón armado y pretensado, estructuras de sección mixta, etc. Se espera que todos estos temas sean de ayuda para abordar conceptos más avanzados de cursos posteriores y desarrollos más profundos en el ejercicio profesional.

  Abstract
  Este libro está dirigido a la formación de estudiantes de ingeniería, arquitectura y también a ingenieros y arquitectos como base de consulta [...]

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