Sensitivity analysis of imperfect bistable cross-ply laminate in material properties and geometrical parameters

Under specific conditions, asymmetric composite laminates exhibit bistable behaviours, enabling large deflections or shape changes with relatively low energy input, without requiring continuous actuation to maintain a specific shape. Such laminates have received extensive attention in aerospace, energy absorption, and bionic applications. The stable characteristics of bistable laminates under ideal conditions have been extensively studied. However, the preparation process inevitably affects the material properties and geometrical parameters of the laminates, and the theoretical models make it difficult to predict the stable characteristics of the imperfect laminates accurately. This paper focuses on the effects of material properties and geometrical parameters on cross-ply laminates. The theoretical model based on the quadratic curvature hypothesis was proposed, through which the effect of Young’s modulus, shear modulus, square hole defect, thermal expansion coefficient, ply thickness, excess resin layer, and ply angle on the bistable characteristics are investigated. And it is found that Young’s modulus, transverse thermal expansion coefficient, layer thickness, and excess resin layer have a great influence on the stable characteristics of bistable laminates. This paper provides new solutions for accurately predicting the stable configurations of cross-ply laminates and broadens the aerospace applications of bistable composite structures.