Pseudo-bistable pre-stressed morphing composite panels

The pseudo-bistable phenomenon already shown to exist in the case of spherical domes is demonstrated in pre-stressed composite panels. This new concept for morphing structures uses intrinsic material viscoelasticity to actuate the structure passively between its different states. A pseudo-bistable structure is first snapped into a buckled state and allowed to relax under a constant strain. Once the actuation is removed, the structure remains in its buckled configuration for a period of time, before quickly returning to its initial state. In this paper, the principles of the pseudo-bistable behaviour are first outlined using a discrete truss model. An equivalent numerical model is then used to show how the time-dependent behaviour imparted to the structure can be controlled by the choice of the pre-straining boundary conditions. Next, the effect of a composite layup on the pseudo-bistable behaviour is shown, and a volume fraction limit is given. Finally, preliminary experimental results confirm the numerical simulations.