Nonlinear aero thermal flutter postponement of supersonic laminated composite beams with shape memory alloys
Abstract The nonlinear aerothermal flutter instability of a shape memory alloy (SMA) fiber reinforced composite beam subjected to simultaneous actions of thermal and aerodynamic loads is investigated. The Brinson model is used to simulate behaviors of the SMA fibers and the Euler Bernoulli beam theory along with nonlinear von Karman strain field are used for modeling of the beam. Thermomechanical properties are assumed to be temperature dependent. The aerodynamic pressure is modeled based on the quasi steady first order piston theory. The governing equations are solved by means of the Galerkin approach, and flutter and buckling boundaries, natural frequencies and damping ratios are obtained. Effects of various pivotal factors such as SMA volume fraction, prestrain of SMA fibers, location and orientation of SMA fibers on critical flutter dynamic pressure, damping ratio and bifurcation points and paths are studied. The results show that the aerothermal flutter characteristics of the laminated beam can be significantly enhanced by embedding SMA fibers. Moreover, the presence of aerodynamic flow and SMA fibers results in postponement of the bifurcation point and a reduction of the postbuckling deflection. The results of this study are expected to shed a light into enhancing the stability boundaries efficiently by increasing the SMA fiber volume fraction and prestrain.