Analysis Of Mechanical And Electrical Damages Of Piezoelectric Materials With Periodically Distributed Defects

With the wide application of piezoelectric materials, the failure of piezoelectric materials is more intensively studied. There are large numbers of microdefects, such as microvoids, inclusions and microcracks existing in the materials, which case damages. These can evolve to invalidate piezoelectric devices with the constant or cyclic loads. Hence it is necessary to analyze electromechanical damages of piezoelectric materials to guide structural reliability design and predict service life.Based on the constitutive equation of the piezoelectric and the static anisotropic damage constitutive theory for piezoelectric materials, the paper studies the relationship between the effective coefficients and damages in damaged materials. Detailed damage numerical analysis is carried out to acquire the effective electromechanical properties of defected materials by the unit cell method. The mechanical and electric damages of piezoelectric materials with periodically distributed microvoids and inclusions are analyzed and investigated. The quantitative connections between the damages and defect parameters, including inclusion elastic modulus, the defect volume fraction, aspect ratio and conductive property were obtained.The results obtained from this study have prospective significances to reinforce the damage constitutive theory of piezoelectric materials, and to guide structural reliability design as well to predict service life of such materials.