Bistable hybrid symmetric laminates

Bistable laminates with unsymmetric lay-ups have been studied extensively. In this work a novel type of bistable hybrid laminate with symmetric lay-up is presented. The two stable configurations of the bistable hybrid symmetric laminate are doubly-curved. The two stable configurations have identical curvatures with opposite signs. The bistability of hybrid symmetric laminates derives from the thermal strain mismatch between the metal ply and the 0° composite ply. Finite element analyses (FEA) are performed using ABAQUS and results are compared with a new analytical model which employs piecewise continuous displacement functions. Two bistable hybrid symmetric laminates are manufactured and the stable configurations are measured in experiments. Both FEA and analytical results match experimental results reasonably well. In addition, the influences of various laminates' lay-ups, dimensions and material properties are investigated to gain a thorough understanding of the bistable characteristics of bistable hybrid symmetric laminates (BHSLs).