Research On The Simulation Of Active Control Of FGM Plates & Shells With Piezothermoelastic Couplings

Functionally graded material (FGM) is a new material which assembles many materials'good characteristics to itself. The FGM has been widely used in a large number of engineering structures because it has many good characteristics to fit all kinds of atrocious environment. The use of piezoelectric materials as sensors and actuators for active control purposes has attracted considerable attention of many researchers in recent years. Most studies have focused mainly on finite element models for the analysis of laminated beams, plates and shells with bonded or embedded piezoelectric sensors and actuators. As far as the authors are aware, very limited works can be found in the literature for the active control of FGM structures using piezoelectric materials. The paper uses the weak forms of piezothermoelastic equations and enhanced assumed strain (EAS) method to develop a solid shell element formulation for analysis of FGM plates and shells subjected to temperature gradient. This element can be used as solid element and can also be used to model thin curved shell structures. Even for a thin plate/shell with very small thickness to length ratio, the predictions of this element are satisfactory. A constant displacement-cum-velocity feedback control algorithm coupling the direct and inverse piezoelectric effects is applied to provide active feedback shape/vibration control of the integrated plates and shells. The effects of the constituent volume fractions and the influence of feedback control gain on the static and dynamic responses of FGM structures are examined. The numerical examples demonstrate that the approach proposed in this paper is correct and the newly derived element is robust.