Continuum damage mechanics in piezoelectric ceramics

摘要

Continuum damage mechanics approach is used to predict the failure of piezoelectric ceramics which are widely used as actuators and sensors in smart structures. A continuum damage model is developed for piezoelectric ceramics, and the model is used to investigate the degradation of effective properties of the material due to damage growth. Effective properties of the material are obtained by extending the Mori-Tanaka method to piezoelectric materials. A damage evolution law is proposed to predict the growth of damage with respect to time, and the involved material parameters in the damage evolution law are obtained from the experiments of Tanimoto and Okazaki. The results are obtained assuming all the effective properties of the material degrade as the damage grow, and the degradation is independent of the load history. This degradation should be taken into account to calibrate the sensors, actuators and controllers for the better reliability, maintainability and controllability of smart structures. The effective properties of the material is related to some measurable electrical quantity such as capacitance. Therefore, the state of damage can be predicted just by measuring the capacitance of the embedded piezoelectric ceramics.