脉冲热源激励金属板材缺陷的红外热波检测

Infrared thermal wave detection of metal plates with defects under pulse heat excitation

以含有盲孔缺陷的金属板材试件为研究对象,在闪光灯脉冲热源激励下对试件内部热流的传递过程进行了有限元仿真。在检测参数和分析参数给定条件下,利用脉冲红外热波检测系统测得试件表面最大对比度原始热图,应用FFT变换方法分析了原始热图序列的幅值图和相位图。结果表明,试件表面的最大温差越大,缺陷越容易检测,幅值图的信噪比较大而相位图的探测深度较深。该方法提高了脉冲红外热波检测技术的探测能力。

This paper presents the finite element analysis of the heat transfer process in metal specimens with blind hole defects under flash pulse excitation and concludes that the greater maximum temperature difference of the surface on the specimen result in an easier defect detection. The use of pulsed infrared thermal wave detection produces the primitive thermography with maximum contrast under given test and analysis parameters and the analysis of amplitude and phase images of the primitive thermograph sequences using FFT shows a greater signal noise ratio for amplitude diagram and a greater probing depth for phase diagram. This method gives a greater detection capability of the pulsed infrared thermal wave detection technique.