Influences of Thermal Loads on Nonlinear Response of Thin-Walled Structures in Thermo-Acoustic Environment
Thin-walled structures of future hypersonic flight vehicles will encounter complex loadings and exhibit obvious nonlinear responses. The thermal loads from high speed flow or engine jet flow can cause thermal buckling of thin-walled structures, such as Thermal Protection System (TPS). If the structures are loaded with intense acoustic loads simultaneously, large deflection nonlinear response, including snapthrough, can be induced. Snap-through will give rise to large amplitude stress cycles and non-zero mean stress, which can lessen the fatigue life markedly. Starting from Hookers Law with thermal components, the large deflection governing equations of motion for simply-supported plate under thermo-acoustic loadings are derived. The partial differential equation (PDE) of motion which is difficult to solve is then transformed with Galerkins method to the system of ordinary differential equations (ODE) under modal coordinates. The displacement responses under different combinations of temperature increments and sound pressure levels are calculated by employing Runge-Kutta method. Typical thermo-acoustic responses are predicted: 1) random vibration around pre-buckled equilibrium position, 2) persistent snap-through between post-buckled positions, 3) intermittent snapthrough, 4) vibration around one of the two postbuckled positions. By dividing the restoring force term in the equation into linear term and nonlinear one, the evolutions of each term are obtained to illustrate the mechanism of thermo-acoustic response and the contributions of each force, including shear force, thermal force and membrane force. Thus a further insight into thermo-acoustic response has been achieved.
Thin-walled structures Nonlinear response Snap-through Thermo-acoustic loadings
Yun Dong Sha Zhi Jun Gao Fei Xu
Shenyang Aerospace University, Liaoning Key Laboratory of Digital Technology Simulation and Test Techniques, Shenyang, Liaoning ,110136, P.R. China
国际会议
上海
英文
220-226
2011-10-21（万方平台首次上网日期，不代表论文的发表时间）