Fracture Behaviour of Cracked Functionally Graded Piezoelectric Materials(FGPMs)

摘要

Piezoelectric materials are widely used as sensors, transducers and actuatorsbecause of their excellent electromechanical coupling effect. Due to theadvantages of traditional functionally graded materials (FGMs) in reducingresidual and thermal stresses [1-2], the concept of FGMs has been introduced intopiezoelectric materials. These kinds of new materials are called functionallygraded piezoelectric materials (FGPMs), which possess continuous variation incomposition and properties. The application of new FGPMs in electromechanicaldevices is expected to have advantages over the traditionally used homogeneouspiezoelectric materials in meeting high demands for their lifetime and reliability.For example, the usage of FGPMs replacing layered piezoelectric components inelectromechanical devices, such as bimorph, may avoid failure caused byinterfacial debonding or stress concentration [3]. However, the commonly usedpiezoelectric materials are generally brittle in nature and have tendency todeveloping cracks during manufacturing and service processes. The existence ofcracks may cause the constructive failure of the electromechanical systems.Moreover, these electromechanical systems made of piezoelectric materials areoften being used or considered for using in the situations involving dynamicloading, thus the dynamic fracture analysis of FGPMs is of great importance inmaintaining the mechanical integrity of these systems.