DYNAMIC FATIGUE OF CRACKED PIEZOELECTRIC CERAMICS UNDER ELECTROMECHANICAL LOADING: THREE-POINT BENDING TEST AND FINITE ELEMENT ANALYSIS
DYNAMIC FATIGUE OF CRACKED PIEZOELECTRIC CERAMICS UNDER ELECTROMECHANICAL LOADING: THREE-POINT BENDING TEST AND FINITE ELEMENT ANALYSIS
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DOI：
10.2140/jomms.2009.4.719
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发表时间：
2009-08
影响因子：
0.9
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中科院分区：
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本文通过数值实验相结合的方法研究了机电载荷下压电陶瓷的动态疲劳或缓慢裂纹扩展。采用单边预裂梁试件在零电场和正电场下进行三点弯曲恒加载速率试验，考察电场和加载速率对断裂载荷和裂纹扩展的影响。还采用有限元分析计算了渗透、不渗透和开放裂缝模型的能量释放率，并讨论了电场对能量释放率的影响。然后根据使用测量数据的有限元分析来估计不同加载速率下的裂纹扩展速度与能量释放速率曲线。锆钛酸铅 (PZT) 类压电陶瓷多年来一直用作传感器和执行器。 PZT 陶瓷中的高机械应力和强电场会引起裂纹，从而导致压电设备过早失效。 PZT 陶瓷的性能在机电负载下也容易退化。因此，需要了解压电断裂[Shindo 等人。 2003年； 2005]和疲劳[Cao 和 Evans 1994；林奇等人。 1995]是压电器件高效可靠设计的关键问题。新藤等人。 [2007] 对机电负载下 PZT 陶瓷的静态疲劳行为进行了实验和分析研究。成田等人。 [2007] 还报道了循环机械载荷和恒定电场下 PZT 陶瓷疲劳裂纹扩展的实验和数值研究。随着时间的推移，某些环境可能会影响裂纹的形成和扩展，并且应力水平远低于导致立即发生故障的应力水平。这个过程称为动态疲劳或缓慢裂纹扩展。仅对少数商用陶瓷和玻璃的慢裂纹扩展参数进行了估计，并且没有人研究压电陶瓷对慢裂纹扩展的抵抗力以及电场对动态疲劳行为的影响。在这项研究中，我们报告了机电负载下压电陶瓷动态疲劳或缓慢裂纹扩展的数值和实验检查。垂直于极化方向产生裂纹。采用单边预裂梁法在零电场和正电场下进行三点弯曲恒载荷率测试。还使用有限元分析来评估渗透、不渗透和开放裂缝模型的能量释放率，以及效果
This paper studies the dynamic fatigue or slow crack growth in piezoelectric ceramics under electromechanical loading by a combined numerical-experimental approach. Constant load-rate testing was conducted in three-point flexure using the single-edge precracked-beam specimens under zero and positive electric fields, and the effects of electric field and loading-rate on the fracture load and crack propagation were examined. A finite element analysis was also employed to calculate the energy release rate for the permeable, impermeable and open crack models, and the effect of electric field on the energy release rate was discussed. Crack propagation velocity versus energy release rate curves at various loading-rate were then estimated based on the finite element analysis using measured data. Piezoelectric ceramics of the lead zirconate titanate (PZT) class have been used for a number of years as sensors and actuators. The high mechanical stresses and intense electric fields in PZT ceramics can induce cracking that can lead to premature failure of the piezoelectric devices. The properties of PZT ceramics are also susceptible to degradation under electromechanical loading. Therefore, an understanding of piezoelectric fracture [Shindo et al. 2003; 2005] and fatigue [Cao and Evans 1994; Lynch et al. 1995] is a key issue for the efficient and reliable design of the piezoelectric devices. Shindo et al. [2007] conducted an experimental and analytical study of the static fatigue behavior of PZT ceramics under electromechanical loading. Narita et al. [2007] also reported experimental and numerical examination of the fatigue crack growth in PZT ceramics under a cyclic mechanical load and a constant electric field. Certain environments may affect formation and extension of cracks over time and at stress levels well below that which causes immediate failure to occur. This process is called dynamic fatigue or slow crack growth. Slow crack growth parameters have been estimated for only a few commercial ceramics and glass, and no one has investigated the resistance of piezoelectric ceramics to slow crack growth and the influence of electric field on the dynamic fatigue behavior. In this study, we report numerical and experimental examination of the dynamic fatigue or slow crack growth in piezoelectric ceramics under electromechanical loading. A crack was created normal to the poling direction. Constant load-rate testing was conducted in three-point flexure under zero and positive electric fields using single-edge precracked-beam method. A finite element analysis was also used to evaluate the energy release rate for the permeable, impermeable and open crack models, and the effect