Experimental study on broadband bistable energy harvester with L-shaped piezoelectric cantilever beam

This paper presents an experimental study of the broadband energy harvesting and dynamic responses of an L-shaped piezoelectric cantilever beam. Experimental results show that the L-shaped piezoelectric beam generates two optimal voltage peaks when the horizontal beam size is similar to the vertical beam size. Several optimized L-shaped piezoelectric cantilever beam structures are proposed. Power generation using the inverted bistable L-shaped beam is better. It is observed experimentally that the inverted bistable L-shaped beam structure shows obvious bistable characteristics and hard spring characteristics. Furthermore, the corresponding relationship between the bistable phase portrait and the potential energy curve is found in the experiment. This is the first time that a phase portrait for stiffness hardening of an L-shaped beam has been found experimentally. These results can be applied to analysis of new piezoelectric power generation structures.