Fatigue Crack Growth Experiments of Resonating Micro-Samples
The reliability and optimal design of Micro Electro Mechanical Systems (MEMS) can be achieved only with the determination of material properties at the micro-scale. The major challenges in performing fatigue tests at the micro-scale are related to the accurate measurement of tiny deformations, to the control of very low forces and to the preparation, handling and positioning of μm-sized samples. In order to investigate the fatigue behaviour of MEMS components a new experimental setup based on the Phase Lock Loop (PLL) technique and a continuum mechanical model were developed for the characterization of micro-sized test samples. The main advantage of PLL is the achievable resolution in the crack length measurement, which increases with the decreasing of specimen size. Therefore, micro-beams with notches and without notches were prepared by electroplating Nickel in a SU8 photoresist mold (UV-LIGA). Investigations on the initiation and near-threshold crack growth behavior were performed to improve the understanding of the micro-mechanisms involved in fatigue phenomena.
S.W. Nam, Y.W. Chang, S.B. Lee and N.J. Kim
A. Cambruzzi and J. Dual, "Fatigue Crack Growth Experiments of Resonating Micro-Samples", Key Engineering Materials, Vols. 345-346, pp. 817-820, 2007