An active-passive nonlinear finite element model for electromechanical composite morphing beams

The use of morphing structures aims to increase aerodynamic efficiency, decreasing fuel consumption and aircraft overall weight. Within this context, piezoelectric materials are of great interest in the design of smart structures because the piezoelectric effect is reversible, allowing them to work both as sensors and as actuators. The present work proposes a geometrically nonlinear finite element formulation for composite beams with embedded piezoelectric layers for application in morphing aerostructures. The formulation uses the complete Green strain tensor to account for geometric nonlinearities, and linear piezoelectricity to model the electromechanical behavior. A set of nonlinear equilibrium equations results from the application of variational principles, and is finally solved by means of an iterative-incremental arc length method. The sensitivity of the element to stacking sequence and number of actuators are investigated.