What are the practical limits on the maximum thickness of shell elements relative to the shell dimension?
When using the thick plate formulation, both the bending and the shear deformations are accurately (within the assumptions of the formulation) accounted for. I have attached verification example 2-012 in which 0.1 in x 0.1 in shell elements with 0.5 in thickness are used and the solution obtained from SAP2000 exactly matches independent solution. As a general rule, one would expect that thick-plate effects would become important when the span to thickness ratio is about 20:1 to 10:1, and the adequacy of the formulation would be good for a ratio of down to about 5:1 or 4:1. Note that this is the span of deformation we are talking about here. As the elements are meshed, the elements may actually be thicker than the plan dimension, and that is OK. The important thing to consider is the ration of the span of deformation to thickness. However, please note that all shell elements are approximate and a special case of three-dimensional elasticity. Depending on your specific needs, shell eleme
