Modelling of electric field and stress in piezoelectric composite plates under bending load

Piezoelectric materials have interesting properties for actuator or sensor applications. The direct conversion of electrical to mechanical power is a key property to build lightweight structure. However their small displacement capabilities oblige the designers to put them in amplification structure such as benders. In order to size them at best an accurate model for the stress and electric field is required to use piezoelectric material at its maximum without overcoming the yield stress or the depolarizing electric field. For benders, model based on beam theory usually used failed in evaluating the electric field and the stress. A model considering them as a plate is more suited. In this paper a model which evaluates the variation of the electric field in the layers of piezoelectric laminated plates and takes into account its impact on the stress and the displacement is proposed. A validation based on a 3D finite-element model is performed.