Performance of U/P finite elements subjected to nearly incompressible linear axisymmetric orthotropic conditions

Abstract

Finite element analysis is a vastly expanding field which provides engineers a viable instrumentation to model and measure idealized constitutive stress strain relationships for various complex physical bodies. In the field of Civil Engineering, this tool has proven very useful to analyze problems that do not have a direct closed solution guided by elementary structural mechanics. Within this field, there are many choices of finite elements, and should be chosen by the engineer to best suit the given mathematical model. For structural analysis, displacement based elements are undeniably the most used in practice. However, these elements have limitations and in such cases, other elements should be used. In foundation design, it is important to accurately model soil deformations and stresses. If the ground conditions are proven to be best modeled orthotropic instead of isotropic, then a finite element analysis should be implemented. If the soil is also shown to be saturated and exhibiting an undrained condition, a finite element analysis with standard displacement based elements will produce erroneous results due to the formulation and therefore another choice of finite element must be made. The scope of this work is to graphically show the performance of U/P finite elements subjected to nearly incompressible linear axisymmetric orthotropic conditions and its superiority over standard displacement based finite elements in this situation.