为了确定各红外热成像定量测量方法在深度定量测量方面的检测能力,对深度定量测量方法原理进行了分析,并进行了实验研究。通过在碳纤维层压板反面制作平底孔的方法制造已知深度分层缺陷,采用红外热成像方法对已知缺陷进行检测,从理论上分析温差峰值时间、对数温度偏离时间以及对数温度二阶微分峰值时间与缺陷深度的关系,通过分析确定温差峰值时间法、对数温度偏离时间法、对数温度二阶微分峰值时间法对深度进行定量测量方法的适用性,并利用上述方法对已知缺陷进行深度定量测量分析,确定不同方法对深度定量测量的检测适用性及检测能力。实验结果表明,温差峰值时间法测量深度达到2 mm,对数温度偏离时间法测量深度达到4 mm,对数温度二阶微分峰值时间法测量深度达到5 mm,同时对数温度二阶微分峰值时间法受三维热扩散影响小,检测无需选择参考区域。因此,对数温差二阶微分法所能测量的缺陷深度最大,准确性更高。通过对不同方法进行应用分析,能够明确不同深度定量测量方法的适用范围与检测准确性,为主动式红外热成像方法的定量检测提供依据。

In order to confirm the detection capability and the applicability of quantitative detection methods, the theoretical is analysed and non-destructive testing is executed. First, artificial defect is machined by making a flat bottom hole with known depth and size on the back of the fiber reinforced composite structure. All these characteristic times are all proportional to the square of the defect depth. Experimental results indicate that the detection depth of the method about the time based on the peak temperature contrast is 2 mm, the detection depth of the method about the break time based on temperature difference in the logarithmic scale is 4 mm, the detection depth of the method about time based on the peak second-derivative of the temperature difference in the logarithmic scale is 5 mm. The peak second-derivative time is selected as the characteristic time to calculate the depth because of high reliability and low 3D conduction effect. Through the application analysis of different methods, the application range and accuracy of different depth quantitative measurement methods can be clearly defined. The result provides the basis for the quantitative detection of active infrared thermal imaging method.