涡流热成像裂纹检测中的形状大小影响分析

发布时间：2018-02-13 06:44

  本文关键词： 涡流热成像 裂纹 形状大小 数值模拟　出处：《仪器仪表学报》2016年07期 　论文类型：期刊论文

【摘要】：涡流热成像无损检测技术可以对金属表面裂纹进行快速、准确的检测,但是不同的线圈、试件以及裂纹大小对检测效果影响很大。通过建立感应加热二维模型,选取裂纹处与非缺陷处温差作为特征量,对不同组成部分形状大小对涡流热成像检测的影响规律进行了数值模拟;对比分析了不同裂纹深度下温差随体积深度比的变化规律,采用数据拟合方法研究了相似裂纹检测规律,并提取出试件形状以及线圈形状对检测效果的影响曲线;最后进行了涡流热成像试验验证。结果表明:当裂纹深度较大时,体积深度比影响规律可分为上升阶段、平稳阶段和下降阶段;相似裂纹间温差变化符合二次变化规律;涡流热成像技术可有效检测超大或超厚试件表面裂纹;减小线圈提离、曲率和线径的大小有助于增强检测效果。实际检测过程中,可据此针对不同被检试件采用不同线圈,提高检测能力。
[Abstract]:The eddy current thermal imaging nondestructive testing technique can detect the crack on metal surface quickly and accurately, but different coil, specimen and crack size have great influence on the detection effect. In this paper, the temperature difference between crack and non-defect is selected as the characteristic quantity, the effect of different component shape on eddy current thermal imaging is simulated, and the variation law of temperature difference with volume depth ratio under different crack depth is compared and analyzed. The law of similar crack detection is studied by using data fitting method, and the influence curves of sample shape and coil shape on the detection effect are extracted. Finally, the eddy current thermal imaging test is carried out. The results show that when the crack depth is large, The effect of volume-depth ratio can be divided into three stages: rising stage, stationary stage and descending stage; the variation of temperature difference between similar cracks accords with the secondary variation law; eddy current thermal imaging can effectively detect the surface cracks of super-large or super-thick specimens, and reduce the coil lift. The curvature and diameter are helpful to enhance the detection effect. In the actual detection process, different coils can be used for different samples to improve the detection ability.
【作者单位】： 火箭军工程大学;
【基金】：国家自然科学基金(51575516,51305447) 陕西省自然科学基金研究计划(2016JM6075) 航空科学基金(201509U8004)项目资助
【分类号】：O346.1
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本文编号：1507558