中文摘要：

脉冲调制涡流（PMEC）检测技术是一种新型脉冲涡流（PEC）检测技术,研究发现,该技术相较传统PEC检测技术在金属构件缺陷检测和评估中具有优势。通过集中研究PMEC检测技术与磁场梯度测量（GMFM）技术的有效结合,探究其在金属构件亚表面裂纹检测中的应用关键和技术优势。仿真分析了PMEC磁场梯度信号及其特征,以及金属构件亚表面裂纹PMEC检测的典型扫查曲线,探究和比较了缺陷检测灵敏度。搭建了试验系统,试验进一步验证了仿真分析结论。研究表明：磁场梯度测量与PMEC检测技术相结合,可有效增强亚表面裂纹的检测灵敏度约10%。

英文摘要：

As a new inspection technique extended from pulsed eddy current（ PEC） technique,pulsedmodulation-based eddy current（ PMEC） technique has advantageous over PEC in evaluation of metal component defects inspection. PMEC integrates with gradient magnetic field measurement（ GMFM）,namely GMFM-based PMEC is proposed particularly for inspection of subsurface cracks. The application and technical advantages of the proposed technique are analyzed. Simulate and analyze correlations of GMFM-based PMEC signals and its features,typical scanning curve subsurface cracks PMEC inspection of metal component are analyzed,defect detecting sensitivity is researched and analyzed. Experimental system is built up,conclusion of simulation analysis is verified. Research shows GMFM-based PEC,GMFM combines with PMEC significantly enhances sensitivity of inspection about 10 % on subsurface cracks.