结构非线性机翼的超音速和高超音速颤振

为探讨超音速、高超音速流中二元机翼的气动弹性特性,基于活塞理论计算了作用在翼面上的气动力,运用能量方法建立了系统的运动微分方程,采用Hopf分叉理论确定了系统的临界颤振速度,并考查了系统参数对临界颤振速度的影响;采用等效线性化和数值积分法研究了具有立方非线性刚度系统的极限环响应,二者结果一致.结果表明,在一定的(无量纲)速度范围内(9.48相似文献   

Non-linear aerothermoelastic modeling and behavior of a double-wedge lifting surface

The design of the re-entry space vehicles and high-speed aircraft structures requires special attention to the non-linear thermoelastic and aerodynamic instabilities. The thermal effects are important since temperature environment influences significantly the static and dynamic behaviors of flight structures in supersonic/hypersonic regimes. The dynamic behavior of a double-wedge lifting surface with combined freeplay and cubic stiffening structural nonlinearities in both plunging and pitching degrees-of-freedom (DOF) operating in supersonic/hypersonic flight speed regimes has been analyzed. In addition a third order piston theory aerodynamics (PTA) is used to evaluate the non-linear unsteady aerodynamic loads applied to the wing section. Loss of torsional stiffness that may be incurred by lifting surfaces subjected to axial stresses induced by aerodynamic heating is also considered. The aerodynamic heating effect is estimated based on the adiabatic wall temperature due to high speed airstreams. It is demonstrated that serious losses of torsional stiffness may occur in such lifting surfaces; the influence of various parameters such as flight condition, thickness ratio, freeplays and pitching stiffness nonlinearity are discussed.