The cross-section behavior of shell elements can be determined using numerical integration through the shell thickness or using a cross-section stiffness calculated at the beginning of the analysis.

Calculating the cross-section stiffness at the beginning of the analysis is efficient, but only linear materials can be considered when this is done; calculating the cross-section stiffness during the analysis using numerical integration allows both linear and nonlinear materials to be used.

Numerical integration is performed at a number of section points through the shell thickness. These section points are the locations at which element variables can be output. The default outermost section points lie on the surfaces of the shell.

The direction of a shell element's normal determines the positive and negative surfaces of the element. To define contact and interpret element output correctly, you must know which surface is which. The shell normal also defines the direction of positive pressure loads applied to the element and can be plotted in the Visualization module of ABAQUS/CAE.

Shell elements use material directions local to each element. In large-displacement analyses the local material axes rotate with the element. Nondefault local coordinate systems can be defined. The element variables, such as stress and strain, are output in the local directions.

Local coordinate systems for nodes can also be defined. Concentrated loads and boundary conditions are applied in the local coordinate system. All printed nodal output, such as displacements, also refer to the local system by default.

Symbol plots can help you visualize the results from a simulation. They are especially useful for visualizing the motion and load paths of a structure.