Validation and development of trace-based approach for composite laminates

Abstract

A new mathematical proof for the expression of thickness-normalized stiffness is proposed in this study, and the similar thickness-normalization method is further used to the third order transverse shear deformation theory and stiffness analysis of hybrid laminate. By which, the thickness-normalized transverse shear stiffness matrix and the trace of hybrid laminate are derived. Furthermore, through the statistical analysis of the mechanical properties for 228 kinds of unidirectional composite materials, the accuracy of the concept of master ply is verified. Meanwhile, a special focal point (38°, 0.385) of trace-normalized off-axis stiffness coefficient (Q′11*) is found for nearly all unidirectional carbon fiber reinforced composite materials. Finally, by analyzing the carpet plots of in-plane stiffness coefficients, flexural stiffness coefficients and transverse shear stiffness coefficients for five typical composite materials, the feasibility of trace-based scaling approach is confirmed.