The laminate stiffness matrix (8) is inverted and laminate midplane strains and curvatures evaluated for a prescribed loading:
Laminate strains vary linearly through the thickness as defined in (7) and are evaluated at three locations in each layer: bottom surface, mid-layer and upper surface. Strains are input directly into (3) for calculation of ply stresses in the laminate coordinate system at the same locations. Laminate ply stresses are then rotated into the lamina principal coordinate system by the following stress transformations,