OOFEM – An Object Oriented Framework for Finite Element Analysis

This paper presents the design principles and structure of the object-oriented finite element software OOFEM, which has been under active development for several years. The main advantages of the presented framework include modular design, extensibility, and robustness. The code itself is freely available and is distributed under GNU public license. It provides tools for linear and nonlinear analysis of mechanical and transport problems on sequential and parallel computers.

Triangulation of 3D Surfaces Recovered from STL Grids

In the present paper, an algorithm for the discretization of parametric 3D surfaces has been extended to the family of discrete surfaces represented by stereolithography (STL) grids. The STL file format, developed for the rapid prototyping industry, is an attractive alternative to surface representation in solid modeling. Initially, a boundary representation is constructed from the STL file using feature recognition. Then a smooth surface is recovered over the original STL grid using an interpolating subdivision procedure. Finally, the reconstructed surface is subjected to the triangulation accomplished using the advancing front technique operating directly on the surface. The capability of the proposed methodology is illustrated on an example.

Effect of Stirrups on Behavior of Normal and High Strength Concrete Columns

This paper deals with an experimental investigation and numerical simulation of reinforced concrete columns. The behavior of normal and high strength columns is studied, with special attention paid to the confinement effects of transversal reinforcement in columns with a square cross section. The character of a failure, and the strengths, ductility and post-peak behavior of columns are observed in experiments and also in numerical solution. A three-dimensional computational model based on the microplane model for concrete was constructed and compared with experimental data. The results of the numerical model showed good agreement in many aspects, and proved the capabilities of the used material model.

Novel anisotropic continuum-discrete damage model capable of representing localized failure of massive structures. Part II: identification from tests under heterogeneous stress field

In Part I of this paper we have presented a simple model capable of describing the localized failure of a massive structure. In this part, we discuss the identification of the model parameters from two kinds of experiments: a uniaxial tensile test and a three-point bending test. The former is used only for illustration of material parameter response dependence, and we focus mostly upon the latter, discussing the inverse optimization problem for which the specimen is subjected to a heterogeneous stress field.Comment: 18 pages, 12 figures, 6 table

Mesh Generation Techniques for Sequential and Parallel Processing

: Two robust algorithms for automatic mesh generation are presented. Firstly, an effective sequential implementation of advancing front technique is considered. The model description together with mesh size control is outlined. A detailed strategy of discretization of individual model entities is provided. The computational complexity of the presented approach is discussed and demonstrated on an example. Secondly, a tree based approach for parallel processing is introduced. The parallelization and discretization strategies are clarified and the parallel performance of the algorithm is examined. 1 INTRODUCTION The finite element method is currently the most widely used method for the structural analysis. As the power of the computing systems is steadily increasing the engineering applications of FEM cease to be limited to "simple" problems. The investigation of more and more complex 3D problems is becoming state of the art of the engineering practice. Therefore tools for automated and..