压电薄膜表面贯穿裂纹的有限元分析

基于有限元软件ANSYS数值模拟,计算了激光作用下的压电薄膜表面贯穿裂纹外场应力强度因子和电位移强度因子,并且研究了90°畴变所诱致的畴变增韧行为。首先,求解无裂纹压电薄膜在激光作用下的热-力-电响应,将求得的应力和电位移场反向作用于裂纹面,求解裂纹尖端处的外场应力和电位移强度因子,然后基于小范围畴变理论求解了90°畴变所致的屏蔽应力强度因子。讨论了薄膜表面裂纹的外场应力强度因子、电位移强度因子及屏蔽应力强度因子随激光作用时间和裂纹位置的变化关系,从而预测压电薄膜体系在加热工作状况下的裂纹扩展和断裂行为。

Finite element analysis of surface through-thickness crack in piezoelectric thin film

The surface through-thickness crack in piezoelectric thin film was analyzed based on numerical simulation via ANSYS software, and the switching toughening due to 90° domain switching was studied under the laser irradiation. Firstly, the thermopiezoelectric response in uncracked thin film was solved under the laser irradiation. Then by using the equal and opposite of the above stress and electric displacement fields as the crack surface loading, the applied stress and electric displacement intensity factors at the crack tip were obtained. Lastly, the shielding stress intensity factor due to 90° domain switching was calculated based on the small scale domain switching theory. The variations of applied stress intensity factor, electric displacement intensity factor and shielding stress intensity factor with irradiation time and crack location were discussed. It could be used to predict the crack propagation and fracture behavior for the piezoelectric thin film system operating at heating environment.