Many nanostructures are assumed to be characterized by couple stress effects. Based on the couple stress theory and surface/interface theory, the anti-plane electro-mechanical behavior of piezoelectric composites with a nano-fiber is studied, and the effect of stress and electric displacement at the interface on the size-dependent behavior is examined. By introducing a decoupling function, the governing equations in piezoelectric materials are simplified into two classical governing equations. The displacement and electric potential are expressed by Bessel functions. By satisfying the boundary conditions around the nano-fiber with surface/interface effect, the expanded coefficients are obtained. Excellent agreement with the previous results validates this model. It can be concluded that the interface around the nano-fiber shows greater effect on the stress than that on the electrical fields, and the interface effect increases greatly due to the existence of couple stress. The effect of material properties of nano-fiber on the stress and electric field under different coupling stresses is also examined.
Received 24 June 2013Accepted 12 July 2013Published online 06 August 2013
This work was supported by the National Natural Science Foundations of China (Nos. 11172185; 11272222; and 11272221) and the National Key Basic Research Program of China (No. 2012CB723300).
Article outline: I. INTRODUCTION II. PROBLEM FORMULATION III. DISPLACEMENT AND ELECTRIC POTENTIAL AROUND THE PIEZOELECTRIC NANO-FIBER IV. SURFACE/INTERFACE THEORY IN PIEZOELECTRICNANOCOMPOSITES WITH COUPLE STRESS EFFECT V. BOUNDARY CONDITIONS AROUND THE NANO-FIBER VI. NUMERICAL EXAMPLES AND ANALYSES VII. CONCLUSION