Abstract: When the hypersonic vehicle is in the stage of subduction, high maneuver orbital changing or instantaneous revealing of the location detection equipment, the fast variation of high-heat-flow aerodynamic heating will produce severe thermal shock to the components, such as antenna windows and radome. It is very important for the hypersonic vehicle to determine whether the breakage occurs under the shock of the large heat flux and obtain its fracture time, because the results have great significance to hypersonic vehicle to finally lock up and hit the target. In this paper, a quartz lamp infrared radiation high-heat-flow thermal shock test system was established, and the maximum heat flux of the test system is up to 1.5 MW/m². High speed thermal shock experiments of brittle materials (SiO₂ and Al₂O₃) were performed. The thermal shock simulation is accurate, and the relative error between the controlled result and the pre-set heat flow is less than 1.0%. In addition, using the digital image correlation method, the dynamic changes of speckle image on brittle material surface were recorded in real time during the thermal shock process, and the important data of fracture time were successfully captured. Through analyzing and calculating speckle images, the changes of strain on the surface were obtained before the fracture of the specimen. The experimental results provide an important basis for the safety and reliability design of the signal detection and locking device for hypersonic vehicle, such as permeable antenna window, under high speed and high-heat-flow thermal shocks.

Key words: hypersonic vehicle, thermal shock, brittle materials, fracture time, digital image correlation method