超高速飞行器平尾大迎角气动弹性特性研究

临近空间超高速飞行器在飞行过程中受到外部干扰作用时会出现大迎角飞行姿态，此时需大角度偏转全动平尾进行配平，带来平尾大迎角下的气动弹性问题。采用计算流体力学/计算固体力学/计算热力学（CFD/CSD/CTD）耦合方法分析了一种超高速飞行器全动平尾的气动弹性特性，重点研究了大迎角下平尾的气动响应及结构变形特点。结果表明:各迎角时的气动力曲线均出现波动，随时间变化逐渐衰减至平衡位置。迎角越大，初始振幅越大，气动力系数减小的比例越大，但随时间衰减得越快。平尾存在弯曲/扭转耦合现象，结构变形导致表面压力分布发生变化，使得整体压力减小、升力系数降低，迎角越大现象越明显。平尾最大应力在迎角30°时达1.2 GPa，已达到所用镍合金材料的屈服强度极限。应在结构设计时在翼轴与平尾接触部位附近加强，或在控制方案设计时限制全动平尾的工作角度。结构发生轴向与法向变形，轴向变形主要由气动热引起，法向变形由气动力和气动热共同引起。 

Aeroelastic characteristics of hypersonic vehicle tail at high angle of attack

During the flight of near space hypersonic vehicles, the external disturbances may result in high angle of attack conditions. And the off-design conditions may lead to a large deflection angle of the all-movable tail, which brings aeroelastic problem. Aimed at solving the aeroelastic problems, aeroelastic characteristics were analyzed by the CFD/CSD/CTD coupled method for the all-movable tail, and especially the aerodynamic response and structural deformation were focused on. The results show that aerodynamic response curves fluctuate and gradually decay to equilibrium position. The larger the attack angle is, the greater the initial amplitude is, the larger the proportion of aerodynamic coefficient decreases, and the amplitude decays faster. Bending/torsion coupling deformation occurs in the tail structure, and the structural deformation leads to the change of pressure distribution, the reduction of the whole pressure and the decrease of lift coefficient. The larger the attack angle is, the greater the decrease is. The maximum stress of the tail reaches 1.2 GPa at 30° angle of attack, which has reached yield strength limit of the nickel alloy material. It should be strengthened for the region where wing axis contacts with tail, or it should be limited for the operating angle in control law design. Axial deformation is mainly caused by aerodynamic thermal load, and normal deformation is caused by aerodynamic thermal load and aerodynamic force load.