New Families of Hygrothermally Stable Composite Laminates with Optimal Extension-Twist Coupling

摘要

The necessary and sufficient conditions for hygrothermal stability of laminated composites are presented. Anthorough survey of hygrothermally stable families is performed to identify stacking sequences that producenmaximumextension-twist coupling.This is achieved through a constrained optimization routine,where the objectivenfunction is derived fromthe constitutive lawgiven in classical lamination theory and the constraints are the necessarynconditions for hygrothermal stability. A representative sample of these optimized laminates are constructed andntested to demonstrate significant improvement in coupling over the previously known optima. Comparisons arenmade with a nonlinear model and finite element analysis. An investigation of the robustness of the optimal stackingnsequences to errors in ply angle typical of hand-layup manufacturing is presented.