Active Snap-Through of Piezocomposite Shells as a Morphing Mechanism

摘要

A theoretical framework for analyzing the coupled nonlinear response of multi-stable doubly-curved adaptive composite shells with attached piezoelectric actuators, subject to applied mechanical, electric and thermal fields is presented. The mechanics incorporate the geometric nonlinearity due to large displacements, rotations as well as the initial stresses. The total Lagrangian formulation is combined with the Hamilton's virtual work principle, in order to derive generalized equations of motion in variational form. An 8-node nonlinear coupled isoparametric shell element is subsequently formulated and encompassed into a multiphysics research finite element code. The nonlinear coupled system is linearized and solved incrementally at each step using the Newton-Raphson iterative technique together with the cylindrical arc-length method. Results quantify the capability of active cylindrical piezopanels to change their shape, through the snapping phenomenon, under applied bipolar electric fields at the actuators. Finally the nonlinear active response of cylindrical panels under combined electromechanical loads, and the influence of the mechanical load on the active transition of the panel is quantified.