脉冲涡流热成像裂纹检测机理仿真分析

Simulation analysis of crack detecting mechanism using pulsed eddy current thermography

脉冲涡流热成像技术由于在导电材料缺陷检测中的优势而成为无损检测的热点。本文运用电磁感应原理及热传导理论,建立感应加热数学模型,利用有限元法分析电磁激励热成像检测缺陷的机理。利用COMSOL有限元软件建模分析了导磁材料和非导磁材料中两种基本裂纹slot和notch附近涡流场和温度场的分布情况,通过分析裂纹附近涡流密度大小和温度场的变化曲线,指出检测导磁和非导磁材料裂纹的最佳观测时间以及温度响应,为下一步的裂纹定量检测提供理论指导。

Pulsed eddy current thermography has great advantages in defect detection in conductive materials. In this paper,a mathematical model of induction heating is established with the electromagnetic induction and heat transfer theory. The finite elements method is used to analyze the mechanism of crack detection using electromagnetic stimulated thermography. The distribution of eddy current and temperature field near the crack slot and notch are simulated with COMSOL in magnetic and non-magnetic materials respectively. Through the analysis of eddy current density near the crack and temperature curve, the best observed time and temperature response of crack detecting in magnetic and nonagnetic materials are found. That provides theoretical guidance for the quantitative detection of cracks in the next step.