Absqus - Shell Element - Section Moment

[Yochael1996]

Dear all,

I am using a shell element to simulate a thin plate. I anticipate that the shell element thickness should not affect the section moment, because the closed-form solution for the thin plate bending moment does not involve the plate thickness (the closed-form solution is shown in the picture). However, I noticed that the section moment does change when the shell thickness changes. The amount of changing is small, but I am wondering why this happens. Can someone advise please?
Thanks in advance!

Regards,
Yochael

 

[FEA way]

What is the order of magnitude of these differences ? It might just be something caused by the nature of numerical method.