Shell elements are used to create a mathematical 2D idealization of a 3D structure. They offer computationally efficient solutions for modelling shell structures when compared to solid elements.

The discussion in this chapter applies to 3D finite-strain shell elements such as SHELL181 and SHELL281. Compared to other shells, these shell elements provide more robust nonlinear analysis capabilities, and significant improvements in cross-section data definition, analysis, and visualization.

The method for defining shell sections described here can also be used to define the cross-sectional properties of the layered thermal shell elements SHELL131 and SHELL132. However, information presented here concerning integration points (NUMPT on the SECDATA command) and section properties (SECCONTROL command) does not apply to SHELL131 and SHELL132.