Suppression of Post-Buckling Deflection and Panel-Flutter Using Shape Memory Alloy

A novel concept proposed is the use of Shape Memory Alloy (SMA) to reduce the panel thermal deflection and flutter responses. SMA has unique ability to recover large prestrains completely when the alloy is heated (by aerodynamic heating in the present case) above the austenite start temperature As. During the recovery process, a large tensile recovery stress occurs if the SMA is restrained. In this thesis, a panel subject to the combined aerodynamic and thermal loading is investigated. A nonlinear finite element model based on von Karman strain displacement relation is utilized to study the effectiveness of SMA embedded panel on the flutter boundary, critical buckling temperature and post-buckling deflection. The study is performed on an isotropic panel, with embedded SMA fibers using finite element analysis. The aerodynamic model is based on the first order quasi-steady piston theory. The aerodynamic pressure effect on the buckling temperature of the panel is investigated by introducing the aerodynamic stiffness term. The influence of the temperature elevation on the flutter boundary is also investigated. The flutter boundary is predicted iteratively by changing the value of the nondimensional dynamic pressure and monitoring the non-dimensional frequency that is characterized by having real values below the flutter boundary. The post-buckling deflection of the panel with SMA embedded fibers has shown a significant decrease compared to that of the panel without SMA. The dynamic and static stability boundaries of the panel when subjected to aerodynamic loading were significantly increased as well. It is concluded that the SMA embedded panels possess enhanced thermal and dynamic properties that qualify them to be an excellent solution for panel-flutter suppression problem.