An electromechanical cohesive zone model merging with contact and friction effects for fiber debonding and pushing-out in piezoelectric fiber composites

Abstract

Owing to electromechanical coupling of piezoelectric fiber composites, they have been widely used in sensing and active control of aeronautic and aerospace structures. In order to describe the interface fracture of piezoelectric fiber composites, a micromechanically motivated interface model based on a cohesive zone model is developed, and it is closer to the actual debonding process including contact and friction effects. In this study, the proposed interface model is formed through incorporating contact effect and a Coulomb friction law into a bilinear traction-separation law, and the electromechanical relationships across separated and contacted crack surfaces are provided. And for purpose of analyzing single piezoelectric fiber debonding, an axisymmetric model and its double series solution are adopted. Comparing with existing experiment and simulation results, the proposed model takes the friction related to the normal pressure varying with the gap between crack surfaces into account, and it is able to qualitatively capture salient features of the experimental record, and guarantee a smooth transition from cohesive debonding to frictional sliding. Furthermore, the piezoelectric fiber push-out behavior is investigated including initial perfect bonded, partial debonding with interface softening and frictional sliding after complete debonding. The dependences of different parameters, such as fiber radius, fiber length, electric field and interface properties, on the load-displacement curve and the responses around piezoelectric fiber are also investigated. It can be revealed that piezoelectric fibers can be designed to monitor and tailor the fracture behavior of composites.