Stable Generalized Finite Element Method Applied to Bidimensional Problems of Linear Elasticity
This work aims to present the topic about the Method of Generalized Stable Finite Elements (SGFEM) as to its efficiency in generating approximate answers to plane problems of linear elasticity. The origin of the SGFEM begins first with the appearance of the Finite Element Method (FEM) and the Generalized Finite Element Method (GFEM). The FEM after several decades being applied, in the most diverse types of analyzes, in the field of structural mechanics, has some disadvantages and limitations in certain applications. To overcome these limitations, the SGFEM emerged. The GFEM, in summary form, is the union of the FEM with the nodal enrichment technique. However, the nodal enrichment is the extension of the original FEM approaches without adding nodes to the original finite elements. It is also emphasized that the GFEM itself has problems related to numerical stability, causing some changes in its formulation to be developed and that originated a new method, SGFEM. Thus, in this work, the objective is to deepen the knowledge about SGFEM, as well as to analyze and test the SGFEM for simulation of linear elasticity plane problems. Specifically, the SGFEM is a modification of the GFEM in order to solve the problem of stiffness matrix and the elements located in the transition region between the enriched and non-enriched area. In this work computational routines are used in Fortran and Matlab for analysis of the topics involving the SGFEM and which are relevant to mention as: hierarchical enrichment, error analysis (using energy norm) and numerical integration. The results obtained so far showed the influence of the interpolant (element of the SGFEM nodal enrichment structure) present in the SGFEM formulation with respect to the elimination of grade 1 monomials and that served the importance of enrichment being hierarchical. It was also observed the improvement in the stress field response and the possibility of using a lower degree of discretization when the enrichment is employed. The MEFGE for crack problems as well as the importance of fracture mechanics concepts are approached aiming to guide the reader to understand the peculiarities of the method and to demonstrate through studies and comparisons the analogy of reference models with real situations of structural mechanics.