目的 验证一种喷涂层下基体疲劳裂纹红外热成像识别方法。方法 综合采用理论分析、数值模拟和试验研究相结合的方法，基于热波传导理论分析超声波激励下基体裂纹产生的热波与喷涂层裂纹产生的同频率热波，在向涂层表面传播过程中发生的叠加干涉效应，以及由此导致的表面热波相位偏移现象。采用数值模拟手段研究涂层裂纹热波与基体裂纹热波之间的叠加干涉规律，开展喷涂层下基体疲劳裂纹的超声红外热成像检测试验验证该方法的有效性。结果 受到脉冲超声波激励后，基体裂纹与涂层裂纹产生的热波向表面传导过程中会发生叠加干涉效应，并导致涂层表面热波相位发生偏移，低频热波相位偏移现象比高频热波更加明显。结论 采用涂层表面热波相位特征识别涂层下基体中的疲劳裂纹是一种可行且高效的方法。

The work aims to validate a method for fatigue crack identification in the substrate under spray coating. Based on the thermal wave conduction theory, theoretical analysis, numerical simulation and experimental methods were utilized to analyze the superimposed interference effect and the phase deviation of surface thermal wave caused by the thermal wave generated by the substrate crack and the thermal wave with the same frequency generated by the spray coating crack in the process of propagating to the coating surface. Numerical simulation was utilized to investigate the regular pattern of superimposed interference between heat waves emitted from coating crack and substrate crack, and ultrasonic infrared thermal imaging test was carried out to detect the fatigue cracks of the substrate under the spray coating to verify the effectiveness of the method. After being excited by pulsed ultrasonic wave, the thermal wave generated by the substrate crack and the coating crack had superposition interference effect in the process of conducting to the surface, caused the phase deviation of the thermal wave on the coating surface. The phase deviation of the low-frequency thermal wave was more obvious than that of the high-frequency thermal wave. It is a feasible and efficient method to identify the fatigue cracks in substrate under the spray coating by PD.