【作者】 蔡清华；

【导师】 杨世锡；

【作者基本信息】 浙江大学 ， 机械制造及其自动化， 2006， 硕士

【摘要】 板材厚度是衡量板材质量的主要指标之一，板材厚度的精确控制是保证产品质量、节约原材料、提高生产效率的主要因素。因此，研究一种有效可靠的板材厚度检测方法具有非常重要的现实意义。 金属板材多层结构厚度的检测是许多重要领域急需解决的问题，例如复合镀层厚度检测、制板流水线多层板材厚度检测、飞机装配件多层厚度检测等。目前，电涡流检测方法灵敏度高，适用于所有导电材料，造价低，不需要耦合剂，以及可以用于高温、薄板、真空表面等难以检测的特殊场合。 本文是在国家自然科学基金项目“多层导电结构深层缺陷电涡流定量化检测与评估的新方法研究”(编号：50505045)，以及浙江双飞无油轴承有限公司的科研项目“制板流水线多层板厚电涡流在线检测系统研究”的基础上展开研究的。本论文研究的主要内容及章节安排如下： 第一章阐述了多层板厚度检测的现实意义和研究价值，概述了电涡流无损检测技术的发展及应用现状，并综述了虚拟仪器技术的发展及应用。最后结合科研项目提出了本论文的研究内容，给出了论文的总体框架。 第二章采用基于阻抗分析的方法，介绍了电涡流厚度检测基本理论，研究了相关的深层厚度电涡流检测技术及多频涡流检测技术。最后给出了一种电涡流检测中放置式探头的有效磁导率及特征频率的计算及选取方法。 第三章介绍了巨磁电阻效应的原理及应用，并在分析巨磁电阻(Giant Magnetoresis-tance，GMR)传感器原理的基础上，结合深层涡流检测技术提出了一种新的电涡流检测方法，并给出了基于GMR传感器的多层板厚电涡流检测装置的设计方案。 第四章以电涡流检测方法为理论基础，通过引入矢量磁位，建立了四层板厚检测的涡流场模型，并推导了该模型中探头散射场阻抗表达式。最后通过实验验证了该模型的合理性。 第五章结合制板流水线多层板厚在线检测系统的需求分析，提出了该系统的设计方案。最后选择虚拟仪器开发平台，并在此平台上构建了系统的总体框架。 第六章在虚拟仪器平台上，应用图形化编程语言LabVIEW及COM组件混合编程技术，采用模块化的编程思想，开发了制板流水线在线检测原型系统。 第七章对全文的研究及开发工作进行了总结，并结合课题对多层板厚电涡流检测技术进行了展望。更多还原

【Abstract】 Thickness is one of the key factors of the plate quality. The thickness measurement of plate becomes more and more important, especially the thickness measurement of multi-layered plate, so researching an effective method to control the thickness of plate is very important.Supported by a National Natural Science Foundation and a multi-layered plate’s thickness testing system project of a company, this paper researched the multi-layered plate’s thickness testing method and on-line testing system based on the Eddy Current Testing (ECT) method and Multi-frequency ECT technology. The detailed content and chapter arrangement of this paper are as follows:Chapter one: The practice and research meaning of multi-layered thickness testing is expatiated, and current research situation of ECT technology is summarized. At last, combining with the researching projects, the main content and frame of this paper is presented.Chapter two: The basic theories of ECT are introduced; deep thickness ECT technology and Multi-frequency ECT technology are researched. The effective magnetism conductibility and characteristic frequency of the placed eddy-current probe coil is also researched, and a method of their calculation and selection is presentedChapter three: The theory and application of Giant Magnetoresistance (GMR) effect is introduced. Combining with deep ECT technology, a new ECT method is presented and the multi-layered plates ECT set based GMR sensors are designed.Chapter four: A four-layered thickness ECT model based on ECT method is constructed by introducing the magnetism vector, the probe coil impedance mathematical model is investigated, and this model is validated by experiment.Chapter five: System’s scheme based on the requirement of the multi-layered plate’s thickness testing system is presented. Virtual Instrument (VI) and PC flat are selected, and the main frame of this system is designed.Chapter six: Graphic programming language LabVIEW and COM components mixed programming technology are used, the multi-layered thickness testing prototype system is developed based on VI flat.In the end, all of the work in this dissertation is summed up, and the future researches on multi-layered ECT technology are prospected.更多还原