Femap Tips & Tricks: Using Interpolation Elements

One of the inherent characteristics of finite element modeling is that often loads and constraints are applied to the model at node points. This technique can bring about stress concentrations, as these points essentially become singularities in the model.

This tip and trick explores an alternative method of applying boundary conditions that makes use of an interpolation element type, the RBE3, which can connect nodal degrees of freedom without adding any stiffness to the model. This allows a more realistic method of defining constraints and loads (an enforced displacement in this case) on a model that avoids unintended creation of singularities and the consequent stress concentrations.