Test research and numerical simulation on thermal modal of plate structure in 1200℃ high-temperature environments

When the hypersonic aircraft flies at a high Mach number, the plate-like attitude control structures, such as the wings and rudders, will be exposed to an extremely high-temperature environment. In this paper, in order to obtain the thermal modal parameters of structure that are difficult to measure, high-temperature transient heating test system and vibration test system are combined to establish a thermal/vibration test system and the experimental measurement for key vibration characteristic parameters of structure in a thermal-vibration coupled environment up to 1200℃ (e.g. the modal frequency and modal vibration shape) is performed. Meanwhile, the numerical simulation on the thermal modal characteristics of rectangular plate is carried out and the test results are compared with the numerical results. In the test, a self-developed extension configuration of high-temperature-resistant ceramic pole is used to transfer the vibration signals of structure to nonhigh temperature zone, and the acceleration sensors are applied to identifying the vibration signals. Test data are analyzed by a time-frequency joint analysis technique. The tested modal frequencies of the plate in high temperature environments ranging from 200℃ to 1100℃ coincide favorably with calculated results, which verifies the credibility and effectiveness of the proposed experimental methods. The research results can provide an important basis for the dynamic performance analysis and safety design of structure under high-temperature thermal-vibration conditions for hypersonic aircraft.