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 Click here to read more from this article
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