Application of the Hybrid-Mixed Finite Element Method with Stabilized Nodal Enrichment on 2D Problem
This work addresses the development of non-conventional variants of the finite element method for plane elasticity based on the combination of the Stable Generalized Finite Element Method (SGFEM) with Hybrid-Mixed Stress Formulation (HMSF). For the HMSF three approximation fields are involved: stresses and displacement in the domain and displacement on the static boundary. In the combined HMSF-SGFEM approach the enrichment of the stress domain field is provided by the product of the Partition of Unity (PoU) and polynomials enrichment functions. It is noteworthy that the nodal enrichment structure in SGFEM is different from that applied in Generalized Finite Element Method (GFEM). In addition, the resource of the so-called nodal enrichment available by SGFEM and GFEM conceptually enlarges the approximation bases of the stress field of the HMSF, without the need to introduce new nodal points in the domain. The numerical simulation of HMSF-SGFEM was implemented using FORTRAN® and MATLAB® and mainly in Python routines. The performance of this new approach (HMSF-SGFEM) is illustrated and compared with results from classical Finite Element Method (FEM). Finally, the implementations developed in Python for plane linear elasticity problems within the SCIEnCE platform will also be presented. It is also noteworthy that the development of FHMT in SCIEnCE was the greatest contribution of this work, as its versatility allows the study of several problems and the easy application of two types of enrichment, MEFG and MEFGE, with different polynomial functions in the desired nodes.