I am using SW 2012 and I have done a linear and a non linear anlysis on an assembly. One potential glitch I notice is when I plot P! principle stress. P1 for the linear analysis makes sense to me. Each little vector symbol lines up as you would think with the direction of most tensile stress on the parts in the location showning. Direction changes around holes and features as you would expect Non-linear - not so much! P1 shows all the arrows everywhere in the direction of the X axis, P2 as in the direction of the Y axis and P3 the Z axis. P1 shows just like the normal stresses in the X axis as Sx does. In my case it makes no sense as it is perpendicular to the load. The Vonmises tensor plot does make sense in both nonlinear and linear analysis however.
Anyone seen this before?