You use a composite layup to model a part that contains many plies, where each ply is defined by a material, a thickness, and a reference orientation. Composite layups are similar to composite shell or composite solid sections. A ply in a composite section is the same as a ply in a composite layup; however, a composite section always contains the same number of plies. In contrast, a composite layup can contain a different number of plies in different regions. Abaqus/CAE converts a composite layup to its constituent composite sections when you analyze your model. Abaqus/CAE allows you to define three types of composite layups—shells, continuum shells, and solids. For more information, see Composite layups.”