摘要:脉冲涡流检测方法是涡流检测技术的一个新兴分支。本文设计了一套脉冲涡流检测系统,通过实验分析,可根据脉冲涡流信号输出峰值的变化判断裂纹的位置;根据脉冲涡流差分信号输出的峰值及峰值时间判定裂纹缺陷的深度信息利用 Comsol 有限元仿真软件对铝,铜,钨三种非磁性材料和铁这种磁性材料 ,每种材料的上表面和下表面分别设置宽度为2mm,深度1-9mm的缺陷进行建模和相关仿真分析,得出不同缺陷与差分信号一阶导数的变化关系。 该结论为工程实践金属内部缺陷检测提供了一定的参考价值。56874
毕业论文关键词:脉冲涡流;差分信号一阶导数;缺陷检测
Abstract: Pulsed eddy current testing method is a new and developing branch of eddy current testing technology. Design a set of pulsed eddy current testing system, through the experimental analysis, according to the change of pulsed eddy current signal output peak judge the location of the crack; Based on pulsed eddy current differential signal output peak and the peak time for determining the depth of the crack defects information by using the finite element simulation software Comsol for Aluminum , Copper , Tungsten three kinds of non-magnetic materials and Iron this kind of magnetic materials, each material on the surface and under surface, respectively, set the width to 2 mm, 1-9 mm depth of defect modeling and simulation analysis, it is concluded that different defects and the change of the first derivative differential signal. The conclusions for engineering practice metal internal defects detection provides a certain reference value.
Key words: pulsed eddy current; The differential signal first derivative; Defect detection
目录
1.绪论 4
1.1.脉冲涡流检测的背景与意义 4
1.3 脉冲涡流检测技术特点 5
1.4 论文安排 6
2.脉冲涡流缺陷检测系统的理论基础 7
2.1. 涡流效应 7
2.2. 趋肤效应 7
2.3. 脉冲涡流检测系统的工作原理 9
3.Comsol Multiphysics软件 10
3.1.Comsol Multiphysics的基本信息 10
3.2.COMSOL Multiphysics 工作原理 10
4.典型差分信号与一阶导数信号的分析 11
4.1.典型差分信号分析 11
4.2.差分信号一阶导数理论分析 12
4.3.频域特征值分析 13
5.对不同缺陷做仿真 13
5.1.对上表面缺陷做仿真 14
5.2.对下表面缺陷做仿真 16
5.3差分信号一阶导数仿真分析 17
5.4脉冲涡流缺陷频域测试研究 19
结 论 21
参考文献 22
致 谢 23
1 绪论
脉冲涡流检测是这几年发展起来的一种新型的无损检测方式,能够定量检测表面和下表面缺陷。因为脉冲涡流的宽谱,所以只用一次扫描就能检测出不同深度的缺陷。脉冲涡流有很好的检测能力,当前在金属结构的无损检测领域获得了普遍的使用[1]。