中文摘要：

本文提出了一种反射式脉冲红外热波技术中采用对数温度-对数时间二阶微分极小峰值时间作为特征时间进行缺陷深度定量测量的方法.首先,介绍了反射式脉冲红外热波技术的基本原理,在半无限厚平板解的基础上得到了对数温度-对数时间二阶微分极小峰值时间与缺陷深度平方的关系式.其次,利用不锈钢和铝材料制作平底洞试件并得到红外热图序列,提取对数二阶微分极小峰值时间.该特征时间与缺陷深度平方实验结果显示其具有很好线性关系,该线性关系可用于实际缺陷深度定量测量,并讨论了与应用广泛的对数二阶微分极大峰值法相比的优缺点.

英文摘要：

This paper proposes to use minus peak time of second derivative with respect to time on logarithmic curve of temperature versus time as a characteristic time for defect depth prediction in pulsed wave thermography. First, the paper introduces the basic principle of pulsed wave thermography, and constructs the theoretical relation between logarithmic minus peak second derivative time and the square of defect depth based on the solution of semi-infinite body. Then, two specimens of steel and aluminum were manufactured with flat-bottom holes to simulate defects. Thermographic image sequences of those two specimens were obtained by using pulsed wave thermography, and then the logarithmic minus peak second derivative time were extracted. The extracted characteristic time has a very good linearity relation with the square of defect depth, and this linearity could be used for defect depth prediction in practical applications. The advantages and disadvantages of the proposed method and the widely used logarithmic peak second derivative method are discussed.