轴承支撑的舵面热模态试验及支撑刚度辨识

对在大气层内及临近空间内长时间飞行的高超声速飞行器，其舵面的模态特性比固支的翼面更加复杂，除了与舵面自身的弹性模量及内部热应力有关外，还受到根部支撑刚度的较大影响，并且支撑刚度还将受到温度的影响。以轴承机构支撑的舵面为对象，考虑温度对支撑刚度的影响，建立了非固支的全动舵面支撑边界条件。通过设计舵面受热相同、支撑部位受热不同的加热工况，辨识出了连接面两侧温升对舵面支撑刚度的线性影响规律，并验证了辨识结果的有效性。结果表明：在舵面受热相同情况下，降低支撑部位的温升，可以有效减少舵面模态频率受气动加热的影响。研究结果可供安装此类舵面的飞行器防热设计参考。

Thermo-modal test on an axle bearing supported rudder and identification of its supporting stiffness

When hypersonic vehicles fly in atmosphere and near space for a long time, the modal characteristics of their rudders are different from their fixed wings. They are not only taking effects of the elastic module and inner thermal stress of themselves, but also taking effects of the supporting stiffness near the rudder spindles, and the supporting stiffness are also under the influence of temperatures. A rudder supported by axle bearing is studied, and the effects of temperature on supporting stiffness are taking into account. Instead of adopting fixed boundary condition at the root of the rudder, a full motion rudder supporting boundary condition is setup. A heating test case is designed, in which the rudder has the same heating condition as the previous test, but the supporting area is different. A linear relationship is obtained, showing how the temperatures rising at the two sides of the spindle have effects on supporting stiffness of the rudder. In the second test case, the identification of the linear relationship is verified as effective. With the same heating condition of the rudder, reducing the temperature of the supporting area will effectively mitigate the influence of aerodynamic heating on modal frequencies of rudder, which can be referred to by the thermal protection design of vehicle with such a rudder. Some suggestions are given for the thermal protection design for vehicles with such rudders.