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在超声红外热像检测中,激励强度、激励时间和工具杆与被测对象之间的预紧力等检测条件是影响缺陷热信号的重要因素。实验和仿真分析表明:激励时间和激励强度的增加将使裂纹生热增强,而预紧力的增加却使得裂纹生热呈现先增强后减弱的趋势,且检测条件对裂纹生热存在交互影响;另外,不恰当的检测条件将导致超声激励系统报警。基于检测条件对裂纹热信号和报警数据的影响分析,文中提出了采用多元非线性回归模型和Logistic回归模型以估算特定检测条件下裂纹检出概率和检测报警概率,最终确定了检测条件的选择范围。上述检测条件的优化方法能够为超声红外热像检测技术中检测方案的制定提供理论指导。
In the ultrasonic infrared thermal imaging detection conditions such as excitation intensity, excitation time and the preload between the tool bar and the measured object are the important factors affecting the thermal signal of the defect. The experimental and simulation results show that the increase of excitation time and excitation intensity will increase the heat generation of the crack, while the increase of the pretightening force makes the heat generation of the crack first increase and then decrease, and the detection conditions have an interactive influence on the heat generation. In addition, improper testing conditions will cause the ultrasound system to alarm. Based on the analysis of the influence of detection conditions on the thermal signal and alarm data of crack, the paper proposed using multivariate nonlinear regression model and Logistic regression model to estimate the probability of detection and the probability of detection alarm under certain detection conditions, finally determined the selection range of detection conditions . The above optimization of the detection conditions can provide theoretical guidance for the development of the detection scheme in the ultrasonic infrared thermal imaging detection technology.