固体火箭发动机壳体脱黏缺陷的热波检测

Debond defect detection in shell of solid rocket motor by thermal wave nondestructive testing

基于热波技术,对固体火箭发动机复合材料壳体/绝热层脱黏缺陷进行检测研究,采用去除背景和分水岭方法对热图进行降噪、增强和分割处理,利用表面热斑区域的面积对缺陷尺寸进行估算,根据热图序列的时间特征计算缺陷的深度,并与声-超声检测结果进行比较.结果表明,热波技术检测速度快,20 s可对缺陷准确定位,检测结果直观;5 mm深的3个缺陷最佳检测时间均为7 s;缺陷深度通过材料参数和缺陷尺寸进行计算,且缺陷越大,误差越小;与声-超声技术相比,热波检测更适合进行定量分析.

Based on thermal wave nondestructive testing technique, debond defects between composites shell and insulation layer of solid rocket motor （SRM）were inspected by numerical analysis and experiment. The thermal images were enhanced and segmented by subtracting background method and watershed algorithms respectively. The hot spots area and the time characteristics of thermal sequence diagram were applied to quantificationally estimate the defects size and depth. The sample was also inspected by acoustic-ultrasonic （AU） method for comparing testing effect. The results show that thermal wave technique has the disadvantage of fast, which can accurately test defect within 20 s; A best inspection time is exited, which was estimated at 7 s in experiment of the three 5 mm-deep defects; defect depths could be calculated by the material parameters and the estimated defect sizes. And the bigger of the debond area, the easier to be detected ; the thermal images were more suitable for quantificational analysis than that by AU method.