Energetic Convergence of a New Hybrid Mixed Finite Element

摘要

This paper presents a new hybrid double mixed stress (4f-HMS) model, for the static analysis of isotropic plane structures, in which it is assumed a physically and geometrically linear behaviour. The main improvement of this model is, it approximates independently the three most important fields in the domain, more specifically the strain field, the stress field and the displacement field of each element. The displacements along the static boundary, considered to include inter-element boundaries, are also directly approximated. For the approximation functions in the space domain, a complete set of orthonormal Legendre polynomials are used. The adoption of these functions enables the use of analytical closed form solutions, for the computation of all linear structural operators, and leads to the development of very effective p- refinement procedures. The model being discussed is tested in terms of convergence capabilities using classical elastic strain energy and other common variables, in which the monotonic convergence is tested. To validate the model and to illustrate its potential, several numerical examples are discussed and comparisons are made, with solutions obtained using analytical results and other known finite element formulations.