The effects of cubic stiffness on fatigue characterization resonator performance
Abstract
Micromachined, kHz-frequency resonators are now routinely employed as testing structures to characterize the fatigue degradation properties of thin film materials such as polycrystalline silicon (polysilicon). In addition to stress-life (S-N) fatigue curves, important properties such as crack propagation rates may be inferred from proper resonant frequency measurements throughout a fatigue test. Consequently, any nonlinear dynamic behavior that would complicate the interpretation of resonant frequency changes should be avoided. In this paper, nonlinear frequency-response curves of a polysilicon fatigue structure are measured in a vacuum environment. Finite element models of the structure are used to identify the source of geometric nonlinearity leading to a Duffing-type cubic stiffness. Given the origin of the behavior, a parametric optimization strategy is performed to minimize the cubic stiffness. This study highlights the importance of considering the dynamic behavior when designing resonating structures, especially when they are used for mechanistic studies in various environments.
Keywords
MEMS resonator; Duffing behavior; Fatigue testing, SILICON STRUCTURAL FILMS; HIGH-CYCLE FATIGUE; OPTIMAL SHAPE DESIGN; POLYCRYSTALLINE SILICON; MICROELECTROMECHANICAL SYSTEM; PARAMETRIC RESONANCE; CRACK-GROWTH; THIN-FILMS; COMB DRIVE; MEMS
DOI
10.1016/j.sna.2009.11.020
Citation
Sensors and Actuators A: Physical Volume 157, Issue 2, February 2010, Pages 228–234
Date of this Version
2-2010
Recommended Citation
Budnitzki, M; Scates, M C.; Ritchie, R O.; Stach, E A.; Muhlstein, C L.; and Pierron, O N., "The effects of cubic stiffness on fatigue characterization resonator performance" (2010). Birck and NCN Publications. Paper 668.
http://dx.doi.org/10.1016/j.sna.2009.11.020