The present paper summarizes the generalized ®nite element method formulation and demonstrates some of its advantages over traditional ®nite element methods to solve complex, three-dimensional (3D) structural mechanics problems. The structure of the sti€ness matrix in the GFEM is compared to the corresponding FEM matrix. The performance of the GFEM and FEM in the solution of a 3D elasticity pro...

The authors have been developing a crack propagation analysis system that can deal with arbitrary shaped cracks in threedimensional solids. The system is consisting of mesh generation software, a large-scale finite element analysis program and a fracture mechanics module. To evaluate the stress intensity factors, a Virtual Crack Closure-Integral Method (VCCM) for the second-order tetrahedral fi...

Finite element modelling of three dimensional elasticity problems gives rise to large sparse matrices. Various preconditioning methods are developed for use in preconditioned conjugate gradient iterative solution techniques. Incomplete factorizations based on levels of fill, drop tolerance, and a two level hierarchical basis are developed. Various techniques for ensuring that the incomplete fac...

A grid re nement scheme has been developed for tetrahedral and triangular grid-based calculations in message-passing environments. The element adaption scheme is based on edge bisection of elements marked for re nement by an appropriate error indicator. Hash table/linked list data structures are used to store nodal and element information. The grid along inter-processor boundaries is re ned con...

We consider H(curl, Ω)-elliptic variational problems on bounded Lipschitz polyhedra and their finite element Galerkin discretization by means of lowest order edge elements. We assume that the underlying tetrahedral mesh has been created by successive local mesh refinement, either by local uniform refinement with hanging nodes or bisection refinement. In this setting we develop a convergence the...

Objective functions for unstructured hexahedral and tetrahedral mesh optimization are analyzed using matrices and matrix norms. Mesh untangling objective functions that create valid meshes are used to initialize the optimization process. Several new objective functions to achieve element invertibility and quality are investigated, the most promising being the “condition number”. The condition n...

This paper examines the effect of curved boundary continuity on finite element simulations. Quartic C0 continuous and G1 continuous meshes with curved boundaries are created from CAD geometry. These C0 continuous and G1 continuous surface triangles are constructed using Bézier triangles and triangular Gregory patches respectively. Curved tetrahedra are constructed using a shape blending with te...