Abstract
Multistable composite elements are a convenient approach to realise morphing or shape-adaptable structural systems. This property is particularly important, for example, in the aeronautical industry where morphing structures can be exploited for better aircraft performance and operational versatility. In this paper it is proposed to study the dynamics of a bistable square plate with pinned boundary conditions using a simplified single-degree-of-freedom (SDOF) model. Initially the numerical load-deflection characteristic of the centre of a plate pinned at the four corners is obtained from a finite element model (FEM) using ABAQUS. This curve was then adjusted to account for the change in material properties due to exposure to moisture and others ambient variables. The dynamic response of the plate was simulated by solving the equation of motion numerically. A test rig was designed and built. The bistable plate was hinged to two beams which are rigid in the vertical direction but allow for horizontal displacement. As predicted, the measurements show that the response of the plate to an harmonic excitation of the base is periodic for a low amplitude of excitation. For large excitation, a snap-through (passage from one stable state to the other) takes place. Ideally, if the boundary condition were symmetric, the chaotic passage from one stable state to another could be observed (as for a system with a double-well potential). However, in practice ideal boundary conditions cannot be achieved and the load-deflection characteristic is not symmetric. As a result, the frequency and the amplitude at which the snap occurs depends on the initial stable configuration. © 2008 by the Katholieke Universiteit Leuven Department of Mechanical Engineering All rights reserved.