Numerical characterization of functionally graded active materials under electrical and thermal fields

This paper deals with a class of functionally graded materials (FGMs) called active FGM that has electro-thermo-elastically graded material phases. The focus is on the characterization of active FGM under electrical and thermal fields. The structure comprises a substrate, an electro-thermo-elastically graded layer and an active layer. Using augmented piezoelectric constitutive law, the effect of temperature on the piezoelectric properties is incorporated in the model. A formulation for exact solutions of the system based on Euler-Bernoulli theory is presented. Polynomial compositional variations of the constituent phases in the graded layer are considered and their performance for a range of stiffness and electrical property ratios of the active and substrate materials is studied under electrical and thermal fields. The effect of temperature dependence of piezoelectric coefficients on the stress distribution in the active FGM is discussed. It is also observed that the compositional variation significantly influences the actuation authority of graded materials depending on the modular ratio of the constituent materials.