ABSTRACT
Solving 3D problems is usually much more difficult due mainly to the complexity of the geometry. When the FEM is used, meshing a complicated 3D domain with quality elements can be quite a daunting task to any analyst. The four-node tetrahedral element (T4) is often used for 3D problems, because of its simplicity in formulation and implementation: piecewise linear approximation of displacement field and constant strain field. Most commercially available FEM codes use tetrahedral elements for adaptive analyses of 3D problems, due to the simple fact that tetrahedral meshes can be most automatically generated and refined for complicated geometrical domains. The FEM-T4 is thus clearly superior at least for two counts: simplicity and adaptation.
