Control of postbuckling mode transitions using assemblies of axially loaded bilaterally constrained beams

Multistable structural members are extensively used in various fields, including microelectromechanical systems (MEMS) actuation, sensing, and energy harvesting. The multistable configuration of elements can be obtained through their elastic postbuckling response. Under quasi-static excitations, the snap-through transitions of buckled elements constitute a useful tool to generate high-rate excitations for piezoelectric transducers. Yet, more efficient energy harvesting and accurate sensing requires that buckling events happen at specific loading levels. This paper investigates the control of snap-through events by using beam assemblies. Multiple bilaterally constrained beams were arranged in parallel and subjected to axial displacement-controlled loading. Experimental studies show that snap-buckling transitions can be controlled by changing the geometry of the assembled beams. An analytical model was developed to investigate the effect of system parameters on its postbuckling response. Results show that transitions are mainly controlled by the beams' thicknesses and lengths. By tuning both parameters, the system can be designed to snap at a desired axial displacement. In this paper, the assemblies were designed to transition at equally spaced axial displacements. However, other displacement combinations can be achieved.