Size effect of flexible proof mass on the mechanical behavior of micron-scale cantilevers for energy harvesting applications

Abstract

Mechanical behavior of micron-scale cantilevers with a distributed, flexible proof mass is investigated to understand proof mass size effects on the performance of microelectromechanical system energy harvesters. Single-crystal silicon beams with proof masses of various lengths were fabricated using focused ion beam milling and tested using atomic force microscopy. Comparison of three different modeling results with measured data reveals that a "two-beam" method has the most accurate predictive capability in terms of both resonant frequency and strain. Accurate strain prediction is essential because energy harvested scales with strain squared and maximum strain will be a design limit in fatigue. (C) 2011 American Institute of Physics. [doi: 10.1063/1.3663858]