针对固体火箭发动机在存放期间粘结界面易出现脱粘的情况,采用超声纵波对其一二界面粘结质量进行检测,得到的二界面脱粘缺陷回波信号通常混叠了一界面多次反射透射的信号,无法与一界面粘结信号区分。为了区分不同界面回波信号,选用EMD(经验模态分解)对回波信号分解,并根据相关性系数得到信号主导作用模态分量,提取其检测信号幅度特征,得到界面粘结情况,再根据时间确定粘结位置是一界面还是二界面。结果表明:通过EMD对超声回波信号的特征提取可以实现固体火箭发动机界面最小直径为4 mm的脱粘缺陷检测,同时有效地降低分析计算的数据量,为固体火箭发动机粘结检测提供一定基础。
Since the solid rocket motor interface bonding is prone to debonding during its storage, ultrasonic longitudinal wave is used to detect the bonding quality of the first and second interfaces, the second interface debonding defect signals are usually mixed with multiple reflection and transmission signals of the first interface, resulting in that it cannot be distinguished from the bonding signal of the interface. To distinguish the echo signals of different interfaces, EMD (Empirical Mode Decomposition) is first used to decompose the echo signal and get the dominant modal component of the signal according to the correlation coefficient, then the interface bonding situation is obtained by extracting amplitude characteristics of the detected signal, finally, whether the bonding position is the first interface or the second interface can be determined according to the time. The results show that the features of ultrasonic echo signals extracted by EMD can realize the detection of debonding defects with a minimum diameter of 4mm in the solid rocket motor interface, besides, EMD can reduce the data quantity of analysis and calculation effectively, providing a certain basis for solid rocket motor bonding detection.