STATIC AND DYNAMIC ANALYSIS OF A BISTABLE PLATE FOR APPLICATION IN MORPHING STRUCTURES A. Carrella 1 , F. Mattioni 1 , A.A. Diaz 1 , M.I. Friswell 1 , D.J. Wagg 1 and P.M. Weaver 1 1 Department of Aerospace Engineering University of Bristol, Bristol BS8 1TR, UK e-mail: A. Carrella@bristol.ac.uk Keywords: Morphing, bistable plate, Duffing ABSTRACT The need for better aircraft performance is increasingly prompting designers towards the reali- sation of morphing or shape-adaptable structural systems. One way to achieve this is to employ multistable composites elements. In this paper a square, curved bistable plate is studied. The finite element analysis provides the load-deflection characteristic of the bistable plate. A cu- bic expression is then fitted to this curve, and the equation of motion of the plate is reduced to a single-degree-of-freedom (SDOF) system which has the form of the Duffing equation for a double-well potential system. The dynamics of the plate are investigated using bifurcation diagrams and shows that the qualitative behaviour given by the measured response is predicted well by the simple SDOF model. 1. INTRODUCTION Morphing or shape-adaptable structural systems are increasingly being considered as a solution to the always present need for better aircraft performance. Such systems should simultaneously fulfil the contradictory requirements of flexibility and stiffness. So far the solutions adopted consist of complex assemblies of rigid bodies hinged to the main structure and actuated. To enhance the performance of the aircraft as a system, multistable composites could provide an interesting alternative to traditional designs, thanks to their multiple equilibrium configurations. Unsymmetric laminates exhibit out-of-plane displacements at room temperature even if cured flat. These displacements are caused by residual stress fields induced during the cool-down pro- cess between the highest curing temperature (∼ 160 ◦ C) and room temperature (∼ 20 ◦ C). The thermal stresses are mainly caused by the mismatch of the coefficients of thermal expansion of constituent layers [1–5]. The main feature of a bistable structure is the snap-through mecha- nism which marks the passage from one stable position to the other. It is clear that an analytical dynamic analysis of the bistable plate would reveal very complicated behaviour. However, the analysis of an accurate Finite Element (FE) model would have a high computational cost. Therefore, in this paper it is proposed to model the dynamics of the snap-through mechanism E213