Flutter and thermal deflection suppression of composite plates using shape memory alloy

An efficient finite element method for predicting critical temperature, postbuckling deflection and flutter response is developed for composite plates embedded with prestrained shape memory alloy (SMA) fibers. The large panel deflection and the temperature-dependent material properties of SMA and composites are considered in the formulation. The finite element formulation and solution procedure of the incremental updated Lagrangian method for nonlinear temperature-dependent material properties are presented briefly. Flow yaw angle at supersonic speed is also considered. For the static solution, the system equations are solved by using the Newton-Raphson iteration method to determine aerothermal postbuckling deflection under the combined aerodynamic and thermal loads. For the dynamic flutter response, the modal method and time-domain numerical integration are employed. Results show that the critical buckling temperature can be raised high enough so that buckling deflection can be eliminated,, and the desired flat and stable region in the temperature-dynamic pressure operating domain can be enlarged greatly for composite surface panels embedded with SMA for supersonic vehicle applications. Weight savings based on critical temperature when SMA is used are also presented.