Design of Hygrothermally Stable Laminated Composites for Extension-Twist Coupling

摘要

Previous attempts to design elastically tailored composites focused first onobtaining the desired coupling, then trying to meet hygrothermal stabilityconstraints. An alternative approach is developed where laminates with optimalextension-twist coupling are selected from families of stable stacking sequencesderived from material-independent hygrothermal stability conditions.Hygrothermally stable stacking sequences with maximal extension-twist couplingare calculated for several material systems using a developed optimizationprocedure and are shown to possess higher coupling than previously known stablefamilies. Trends in the coupling behavior are discussed, and results are verifiedwith non-linear finite element analysis. The ratio of fiber stiffness to matrixstiffness is found to be a dominant parameter in the magnitude of the coupling thatcan be achieved.