Courtroom FEA: But my expert has hand calculations

Hand calculations are good.
It is very important that design engineers do hand calculations. It is very important that engineering expert witnesses do hand calculations.
For everything but the simplest of part geometries, hand calculations of stress are generally rough estimates. Often they are only in the ballpark of the true maximum stress levels. Sometimes they are only in the ballpark of the average stress levels, and miss the highest stresses entirely.
In the span of 50 years, finite element analysis has gone from esoteric research topic to widely available, widely applied mature technology. In the 1980's, FEA required extremely expensive mainframe computers, very expensive FEA codes and highly trained analysts, and was still implemented at many larg View the rest of this article