Comparative study about the cantilever generators with different curve fixtures

Magnetic interaction and pre-stress effect are two regular ways of introducing nonlinearities for wideband energy harvesting. However, the susceptibility to the fabrication and assembling makes it a tough job to exactly tune the magnetic field distribution and the preload as desired for the purpose of avoiding large deviation from design and model, especially in the micro-electro-mechanical systems scale. The nonlinear generator by introducing a curve fixture to the cantilever beam instead of the rectangular fixture presents a feasible and simple solution with good micro-electro-mechanical system fabrication compatibility. In this article, three prototypes of with different curve fixtures with the same size requirement are fabricated for detailing the influence of the selection of the fixture curve. Experimental and numerical investigations reveal that the generator has better performance when the nonlinear stiffness introduced by the curve fixture is smooth, especially in the case of no linear stiffness segment.