Through numerical simulations and experimental validation, we selected the A0 mode Lamb wave, which is more sensitive to interfacial damage, as the incident wave and excited it on the surface of the structure. Displacement time-history response signals at observation points under different damage models were extracted and analyzed, and DEF values were calculated. The results show that DEF values increase with the size of the interfacial debonding damage. Similar trends were observed in experimental studies, further validating the effectiveness of this method and demonstrating that DEF can be used for the quantitative evaluation of interfacial debonding defects in CFRP–rubber bilayer bonded structures.

Solid rocket motors (SRMs) are extensively utilized in aerospace and missile systems because of their simple structure, high thrust, mobility, reliability, and ease of maintenance [1]. To reduce the weight and increase the operational pressure of SRMs, traditional metallic materials in motor casings have been increasingly replaced with carbon fiber-reinforced polymer (CFRP) composites owing to their superior mechanical properties [2,3,4]. The structural configuration of a typical SRM, as illustrated in Figure 1, includes a CFRP shell, an insulation layer, a liner, and a solid propellant from the outside to the inside [5].

In recent years, numerous nondestructive testing (NDT) methods, including X-ray imaging, infrared thermography, and ultrasonic testing, have been developed to detect structural damages in SRMs...

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