Hygro

The tensile strength and compressive strength are indispensable indexes during the design process of composite laminates. For hygro-thermally curvature-stable extension-twist coupled laminates, the improved Differential Evolution Algorithm combined with penalty function is adopted to solve the nonlinear strong constraint of free-layer laminates. The synchronous optimization of multiple targets is achieved, which includes extension-twist coupled effect, tensile strength, compressive strength and buckling strength. Results are presented for free-layer graphite/epoxy composites laminates that consist of 1–18 plies. Finally the hygro-thermal effect, extension-twist coupled effect and buckling strength are simulated and verified