Introduction

With the help of Tarcisio Barreto Celestino and Antonio Bobet, our MIDAS Expert Osvaldo Paiva Magalhães Vitali took on a new approach using midas GTS NX on tunnels with complex ground and loading conditions. In their recent publication in the Soils and Rocks Journal, we can see how they used the features in midas GTS NX to impose body forces to the 3D finite elements; this is done by providing components of the Cauchy stress tensor.

The scary part of FEM is sometimes FEM gives wrong results without any error message. The analysis may be meaningless if an engineer cannot check or interpret the results. Let’s consider a simple example similar to the case from Dr. Gallagher (Finite Element Analysis: Fundamentals, 1975).

For the previous example, we can use high-order triangular elements. This element has six nodes per element and assumes the displacement is quadratic within an element. Also, each side edge can be curved, as shown.

Continuing on to the third part of this multi-part blog, another option is a quadrilateral element. As always, let’s start with an example.