Mechanical behavior of embedded bistable dome shell with tunable energy barrier asymmetry

Abstract

In this work, the mechanical response at finite strains of embedded dome shells is investigated both numerically and experimentally. These systems are interesting as they exhibit up to two stable shapes, a feature that makes them promising candidates for numerous applications from energy harvesting to shape morphing. The energy landscape scenario of these structures presents a major peculiarity as the strain energy required to switch the system between its stable shapes is path-dependent and varies upon loading (i.e. snap-through instability) and unloading (i.e. snap-back instability). This paper proposes to investigate their asymmetrical mechanical behavior. To do so, Finite Element computations were first carried out onto dome shell models, where the geometrical parameters were varied systematically. Specifically, two sets of computations were conducted using the Static Damping Method. The first served to identify the mono- and bistable domains of the embedded dome shells as function of the dome main geometrical parameters. The second focused on bistable dome geometries and explored systematically the asymmetry in the energy barrier required to switch between the two equilibrium states. Interestingly, the results of this study showed that a simple asymmetry indicator could be used to effectively qualify the dome asymmetric bistability, in turn providing simple guidelines for the design of morphing structures with programmable response. Finally, in order to validate the numerical results, the mechanical response of the 3D-printed rubber-like dome shells was measured experimentally using a dedicated set-up that was designed and fabricated to this purpose. The results of experiments were found to be in good agreement with those of simulations.