대한기계학회:학술대회논문집 (Proceedings of the KSME Conference)
- 대한기계학회 2008년도 추계학술대회A
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- Pages.362-367
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- 2008
굽힘 압전 복합재료 작동기의 전기적 피로 거동
Electric Fatigue Behavior of a Bending Piezoelectric Composite Actuator
- 발행 : 2008.11.05
초록
In the present work, we address electric fatigue behavior in bending piezoelectric actuators using an acoustic emission technique. Electric cyclic fatigue tests have been performed up to ten million cycles on the fabricated specimens. To confirm the fatigue damage onset and its pathway, the source location and distributions of the AE behavior in terms of count rate are analyzed over the fatigue range. It is concluded that electric cyclic loading leads to fatigue damages such as transgranular damages and intergranular cracking in the surface of the PZT ceramic layer, and intergranular cracking even develops into the PZT inner layer, thereby degrading the displacement performance. The electric-induced fatigue behavior seems to show not a continuous process but a step-by-step process because of the brittleness of PZT ceramic. Nevertheless, this fatigue damage and cracking do not cause the final failure of the bending piezoelectric actuator loaded up to 107 cycles. Investigations of the AE behavior and the linear AE source location reveal that the onset time of the fatigue damage varies considerably depending on the existence of a glass-epoxy protecting layer.
키워드