高超声速飞行器脆性透波材料大热流冲击下断裂性能试验

高超声速飞行器在俯冲段、高机动变轨或瞬间外露定位探测设备时，快速变化的高热流密度气动热会对天线窗、天线罩等部件产生强烈的热冲击。判断脆性材料透波部件在大热流密度冲击下是否出现断裂破坏及确定断裂时间点，对于高超声速飞行器能否最终锁定并击中目标具有极为重要的意义。本文建立石英灯红外辐射式大热流冲击试验系统，最大冲击热流密度可达1.5 MW/m²，并对SiO₂和Al₂O₃2种脆性材料进行了高速热冲击试验。热流冲击模拟准确，控制结果与预设热流的相对误差小于1.0%。同时，采用数字图像相关方法实时采集热冲击过程中脆性材料表面散斑图像的动态变化，成功捕捉并获得了断裂时间点这一重要关键参数。通过对散斑图像的分析计算，得到了脆性试验件断裂前的表面应变的变化。试验结果为高超声速飞行器透波天线窗等信号探测定位部件在高速大热流热冲击下的安全可靠性设计提供了重要依据。

Fracture performance test of wave transparent brittle materials of hypersonic vehicle under high-heat-flow thermal shock

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.