Software development for adaptive processes: AMVIEW and FESTA experiences

Resumo

Adaptive Processes are very important in computational mechanics. Basically, the idea is the system be able to adapt itself, without the help from the user, converging to a better solution. We developed two software programs to address this problem: initially the Adaptive Mesh View (AMVIEW), which was able to design and implement an adaptive solution and then this software evolved to the Finite Element System Technology in Adaptivity (FESTA), which is a more complete environment for adaptive processes. These works introduce a methodology for self-adaptive numerical procedures, which relies on the various components of an integrated, object-oriented, computational environment involving pre-, analysis, and post-processing modules. A basic platform for numerical experiments and further development is provided, which allows implementation of new elements/error estimators and sensitivity analysis. A general implementation of the Superconvergent Patch Recovery (SPR) and the Recovery by Equilibrium in Patches (REP) is presented. Both SPR and REP are compared and used for error estimation and for guiding the adaptive remeshing process. Moreover, the SPR is extended for calculating sensitivity quantities of first and higher orders. The mesh (re-)generation process is accomplished by means of methods combining quadtree and Delaunay triangulation techniques. Surface mesh generation in arbitrary domains is performed automatically (i.e. with no user intervention) during the self-adaptive analysis using either quadrilateral or triangular elements. The effectiveness and versatility of both software are demonstrated by representative numerical examples illustrating the interconnections among finite element analysis, recovery procedures, error estimation/adaptivity and automatic mesh generation.