Stacking sequence

A single layer of reinforcement within a laminate, such as one sheet of prepreg, fabric or unidirectional tape. Plies are stacked at specified orientations to give the finished laminate its required directional properties.

A laminate whose ply orientations and materials mirror each other about the mid-plane. Symmetry prevents coupling between in-plane loads and bending, so the laminate remains flat after cure instead of warping.

A laminate that contains, for every angled ply, a matching ply at the equal and opposite angle, eliminating coupling between in-plane extension and shear. Balanced, symmetric laminates are the default choice where predictable, distortion-free behaviour is required.

A laminate with equal numbers of plies in three or more equally spaced orientations, giving in-plane stiffness that is effectively the same in every direction. It is the standard conservative layup where load directions are uncertain or vary in service.

A composite element built up from multiple bonded layers (plies) of reinforcement and matrix, consolidated and cured so that they act as a single structural material. Its stiffness and strength depend on the fibre orientations and stacking sequence of the plies.