GT Lab Delta Pic

Elastic Relationships

The constitutive equations for a symmetric angle ply laminate, where each layer has the same thickness, are




and where l = cos and m = sin and the Qij are defined as


The terms C11, C22, and C33 are the laminate stiffness coefficients in the meridian, , hoop, , and shear directions, respectively. The C12 term is the stiffness coupling between the meridian and hoop direction. Strictly speaking, filament wound structures are not symmetric, but alternating plus/minus plys, but because there are generally multiple plus/minus layers, the nonsymmetric aspects of the laminate quickly fade. It is assumed here that the C13 and C23 terms are zero. Since all plies have the same rotation angle, the stiffness terms are the same as in a single rotated lamina.

© 1997 Kurt Gramoll, The University of Oklahoma, All Rights Reserved.