Multistability of Connected Variable Stiffness Laminates

Abstract

AbstractMultistable laminates have been actively researched in the recent past, due to its potential in morphing applications in different engineering sectors. Unsymmetrical cross-ply laminates, which yield two stable cylindrical shapes, are widely investigated multistable structures, where the multistability is induced due to the residual thermal stresses. However, to improve the design space in such laminates, variable stiffness (VS) laminates with curvilinear fibre paths have been investigated recently. They have been found to generate diverse stable shapes, with the possibility to tailor snap-through loads. Connecting two different laminate plates can generate more than two stable configurations, often desired in morphing applications. This study aims to develop a highly multistable continuous composite plate by connecting two square VS laminates without any external fixing aids. A parametric study is performed to understand the effect of VS parameters on the snap-through forces in comparison with the results from conventional cross-ply laminates. The multistable shapes of the series-connected laminates are analysed within a commercially available finite element package. It is concluded from the study that VS laminates can produce multiple equilibrium states with lower actuation requirements, without compromising much on out-of-plane displacements.KeywordsMorphing structuresMultistable structuresVariable stiffness laminatesActuation energyBistable laminates