ShellMITC4 Theory

[ag110]

Dear Colleague

can you please guide me what is theory of shellMITC4.(thin or thick shell).

I transfered model from sap with shell thin element to opensees and substituted thin shell element of sap with ShellMITC4 and
Elastic MembranePlate section of opensees but in the modal analysis resulte from both software are different.
I guess it may due to different theory of shell element.
I appreciate if guide me.

[vesna]

Here is the theory for OpneSees shell element:
http://opensees.berkeley.edu/OpenSees/doc/plate.pdf