A trace-based approach to design for manufacturing of composite laminates

A novel invariant-based approach to describe stiffness and strength of carbon-fiber-reinforced plastic composites has been recently proposed in the literature. In this work, a direct sizing method based on trace of the plane stress stiffness matrix and unit circle failure criterion is proposed. Strength-based profile of a panel is first determined for a baseline material based on the upper-bound value of the calculated failure index k-field from a boundary-value problem. The structural component can then be scaled linearly to meet the stiffness requirements that include deformation, deflection, natural frequency, and buckling. Material selection by scaling is the last step in this sizing method. The proposed approach is conceptually simple to implement, not material specific, and immediately applicable for automated tape laying. Although this is a 2D formulation of an orthotropic homogenized laminate, the 3D stiffness can be separated into two uncoupled in- and out-of-plane submatrices. Thus, the in-plane results of this method are independent of the out-of-plane behavior.