高超声速二元机翼迟滞非线性热颤振

Hypersonic airfoil aerothermoelastic analysis with hysteretic nonlinearities

采用三阶活塞理论计算非定常气动力,考虑高超声速下气动加热对扭转刚度的影响,对具有结构迟滞非线性的高超声速二元机翼进行热颤振分析,比较不同厚度比对二元机翼的线颤振速度的影响。研究结果表明:高超声速气动热效应降低了机翼的颤振速度;机翼的厚度比对热颤振速度有较大的影响,热颤振速度随厚度比的增大而增大。高超声速二元机翼的非线性热颤振表现为极限环振荡,通过poincare截面获得机翼响应振幅的分岔图;系统分岔速度小于线颤振速度,极限环振动的幅值随流速的增大而迅速增大。

The aerothermoelastic of hypersonic airfoil with hysteretic nonlinearities was analyzed,and the third-order piston theory aerodynamic was employed to evaluate the unsteady aerodynamic loads.Also the loss of torsional stiffness induced by aerodynamic heating was considered.The heat-flutter velocity with various thickness ratios was studied.The research results show that the linear flutter velocity increases with the increase of thickness ratios.The airfoil dynamic responses involving limit cycle oscillation,bifurcation behavior are observed over parameters of aerothermoelastic system by time history curve and poincare map.It is found that the bifurcation velocity is less than linear flutter velocity,and the limit cycle oscillation amplitude increases as flight velocity increases.