基于超声导波的返回舱热防护结构烧蚀层厚度监测方法

A method based on ultrasonic guidedwavefor monitoringthe thickness of ablation layer for thermal protection structures of re-entry capsules

摘要: 为实时监测航天器返回舱烧蚀层厚度，文章基于超声导波在双层板结构中的传播特性研究发现导波波速与烧蚀层厚度相关，故提出依据导波波速变化对结构烧蚀层厚度损失进行表征的方法，以及根据导波频散曲线和厚度敏感曲线选择适当的监测模态和频率的方法，可以实现烧蚀层厚度的高效率、高精度实时在线监测。有限元仿真和实验结果均验证了该烧蚀层厚度监测方法的有效性。

Abstract: To monitor inreal time the thickness of the thermal protection structures (TPS) encapsulating the re-entry capsules, this paperproposes a method using the guided wave velocity as a factor to represent the thickness, based on thecorrelation between the wave velocity and the thickness ofthe ablation layer of TPS. The modes and the frequencies are selected based on the frequency dispersion curve and the thickness sensitivity curve, and the thickness loss of the ablation layer is evaluated for highly efficient and high-precision monitoring of the ablation layer thickness in real time. Both the FE simulations and the experiments are performed to validate the effectiveness of this method.