Hi students/peter, With reference to my previous post, you asked me to plot the elements triad for solsh190 elements. It is plotted as below, 

solsh190 triad

As I can see that the Z axis is perpendicular to the thin surface. Can you please let me know how its related to the results difference between shell181 and solsh190.

I have deleted previous post as I was unable to add this content in it.