How to distinguish the 'Tensil' and 'Compression' state for 3D elements?

Hi,

Tension or compression becomes a direct concept in case of 1D problems only. In 3D, there could be tension in a given direction, while compression occurs in some other direction, in most of the problems, at the same point itself.

If you are interested in maximum values of tension (or compression), it may be possible to use first (or third) principal stresses in a 3D analysis. But remember that first principal stress can become compressive at a point/problem, while the third principal stress is tensile at a different point/problem.

Jayadeep