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Development of fracture analysis of piezoelectric ceramics based on the continuum damage mechanics

基于连续介质损伤力学的压电陶瓷断裂分析研究进展

基本信息

批准号：
15560078
负责人：
MIZUNO Mamoru
金额：
$ 2.05万
依托单位：
Akita Prefectural University
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (C)
财政年份：
2003
资助国家：
日本
起止时间：
2003 至 2005
项目状态：
已结题

项目摘要

Variation of material properties of piezoelectric ceramics under cyclic electric loading was evaluated experimentally. A resonance and an anti-resonance frequencies and a capacitance were measured by an impedance analyzer, then an electromechanical coupling coefficient, a permittivity, an elastic constant and a piezoelectric constant were estimated.An electric field with a frequency among 0.1 to 2 kHz was applied to a specimen of lead zirconate titanate (PZT) systematically. Then the dependence of the variation on the range and mean electric field, compressive stress due to the displacement constraint and frequency of negative AC electric field was clarified.An electric field with the resonance frequency was also applied to a specimen and an internal stress in the center of the specimen was estimated by the AC current. It was found that the electromechanical coupling coefficient and the piezoelectric constant of lead titanate specimen were decreased significantly when the internal stress was the largest.A piezoelectric constitutive equation and a damage evolution equation were applied to the double cantilever beam model, and a simplified analysis of crack growth was performed by a local approach of fracture based on the continuum damage mechanics. The effects of the space discretizing size in the numerical analysis and the phase difference between mechanical and electric loading on the crack growth behavior were elucidated.A coupled analysis of stress-electric-damage field for a unit cell associated with multilayer piezoelectric actuators was performed by a finite difference method using the piezoelectric constitutive equation and the damage evolution equation. Then distribution of stress and electric field depending on the damage development, relation between crack initiation time and applied electric field and crack initiation point near the electrode were clarified.

实验研究了压电陶瓷材料在循环电载荷作用下材料性能的变化。利用阻抗分析仪测量了压电陶瓷的谐振频率、反谐振频率和电容，估算了压电陶瓷的机电耦合系数、介电常数、弹性常数和压电常数，并对压电陶瓷施加了频率为0.1 ~ 2kHz的电场。然后阐明了该变化与范围和平均电场、位移约束引起的压应力以及负交流电场频率的关系，并对试件施加谐振频率的电场，由交流电流估算试件中心的内应力。将压电本构方程和损伤演化方程应用于双悬臂梁模型，采用基于连续介质损伤力学的局部断裂方法对裂纹扩展进行了简化分析。分析了数值分析中空间离散尺寸和力电相位差对裂纹扩展行为的影响，采用有限差分法，基于压电本构方程和损伤演化方程，对含多层压电驱动器的单胞进行了应力-电-损伤场耦合分析.阐明了应力和电场随损伤发展的分布规律、裂纹萌生时间与外加电场的关系以及电极附近的裂纹萌生点。