In Virtual.Lab you have the option to select Compute on Node as method parameter. According to the help documentation, this option performs a nodal average of the stress tensor before the durability calculations execution. However, no details are provided in the documention about this kind of averaging.
How this average is executed? Is possibile to have a hand calculation example?
We are assuming a free surface and therefore a plane stress for the analysis. Therefore also the nodal averaging needs to provide a plane tensor. For this one has to know for each element connected to this node:
Normal vector to the surface
Element Nodal stress tensor
Weight factor depending on the element size
First average the Normal vector
Transform the stress tensors into the plane normal to the averaged normal vector
Average the stresses
Eventhogh this gives no instruction for a handcalculation, I hope this helps
Dr.Michael Hack Business Product Line Manager Durability Simulation and Testing Solutions