Tailoring bistability in unsymmetrical laminates using an additional composite strip

Abstract Unsymmetric laminates exhibiting two stable equilibrium shapes due to the induced thermal residual stresses have been extensively explored in recent years. The potential energy wells for such bistable systems have a considerable influence on the stable shapes and their snap-through behavior. For a square shaped cross-ply laminate, both stable shapes, having their principal curvatures orthogonal to each other, possess identical potential energies. However, applications pertaining to morphing systems requiring different snap-through and snap-back forces and the design of metamaterials for wave propagation demands asymmetry in the potential energy landscape. Motivated by such applications, a novel strategy is proposed to realize a tunable potential energy landscape in a square bistable cross-ply laminate by attaching an additional strip. A fully non-linear finite element model is employed to model and analyze an unsymmetrical laminate with an additional strip. The results of the cool-down shapes are verified using a corresponding Rayleigh–Ritz based semi-analytical formulation. A systematic parametric study using the developed finite element method is further performed to explore the changes in the potential energy landscape and its dependencies on geometric parameters like width, thickness, orientation, and the location of the strip. Consequently, the effect of the snap forces on changing the aforementioned parameters are also investigated.