低密度防隔热材料分层缺陷的空气耦合超声检测及分析  

Air-coupled ultrasonic testing and analysis on delamination defect of low-density thermal protection and insulation material

作　　者：肖轲迪 马兆庆[1] 高晨家 陈博 袁生平[1] 罗明[1] 支凡 唐君 余立琼[1] 吴时红[1] 赵建华[1] XIAO Kedi;MA Zhaoqing;GAO Chenjia;CHEN Bo;YUAN Shengping;LUO Ming;ZHI Fan;TANG Jun;YU Liqiong;WU Shihong;ZHAO Jianhua(Aerospace Research Institute of Materials&Processing Technology,Beijing 100076,China)

机构地区：[1]航天材料及工艺研究所,北京100076

出　　处：《复合材料学报》2025年第2期835-844,共10页Acta Materiae Compositae Sinica

摘　　要：低密度防隔热材料是航天飞行器热防护系统的重要组成材料,具有密度低、孔隙率高、热导率低等特点,在轻质的同时具备优异的防隔热性能。但是,该类型材料及其结构特点为材料内部缺陷的无损检测带来较大困难,常规超声喷水穿透法不适用,红外法效果较差。针对石英纤维针刺织物增强酚醛树脂基低密度防隔热材料内部分层缺陷的检测问题,开展了空气耦合超声检测研究。在研究中,通过X射线Micro-CT检测分析了材料的微观结构,估算了分层缺陷声压透射率与空气间隙厚度的关系,制作了密度分别为0.4、0.5、0.6、0.7 g/cm^(3)材料的缺陷试样,并通过空气耦合超声检测搭配50、140、200 kHz频率探头对缺陷试样进行了检测研究。结果表明:空气耦合超声检测能有效发现低密度防隔热材料中的分层缺陷,检测适用频率和检测能力与材料密度和材料均匀性有关。在材料厚度30 mm、分层缺陷空气间隙厚度0.3 mm时,使用频率50 kHz的空气耦合超声探头,在密度0.4~0.7 g/cm^(3)材料中均能发现直径30 mm及以上尺寸的缺陷。The low-density thermal protection and insulation material is an important constituent material on aerospace craft thermal protection system.The material is low density,high porosity,and low thermal conductivity,with lightweight and excellent thermal protection and insulation performance.However,the material and its microscopic structure characteristics cause difficulties on non-destructive testing on the internal defects.The regular ultrasonic transmission testing is unsuitable,and the infrared testing is less effective.To detect the delamination defect of low-density thermal protection and insulation material,which is composed of quartz needled fabric and phenolic resin,the research on air-coupled ultrasonic testing is carried out.The microstructure of the material was analyzed by X-ray Micro-CT detection.The relationship between delamination defect sound pressure transmittance and air gap thickness was estimated.The material specimens with densities of 0.4,0.5,0.6,0.7 g/cm^(3) were made.The research of air-coupled ultrasonic testing on the specimens with probe frequencies of 50,140,200 kHz was performed.The result shows,the air-coupled ultrasonic testing is effective on delamination defect detection of low-density thermal protection and insulation material.The suitable detection frequency and detectability are both related to the material density and the material homogeneity.When the material thickness is 30 mm,the delamination defect air gap thickness is 0.3 mm,the probe frequency is 50 kHz,and the material density is within 0.4-0.7 g/cm^(3),the delamination defect with diameter greater than 30 mm can be detected.

关 键 词：低密度防隔热材料 微观结构 分层缺陷 空气耦合超声检测 Micro-CT检测 

分 类 号：TB553[理学—物理] TG115.28[理学—声学] TB332[金属学及工艺—物理冶金]