电磁加载对金属闭合裂纹超声非线性的调制机理研究

项目名称： 电磁加载对金属闭合裂纹超声非线性的调制机理研究

项目编号： No.51307043

项目类型： 青年科学基金项目

立项/批准年度： 2014

项目学科： 电工技术

项目作者： 张闯

作者单位： 河北工业大学

项目金额： 25万元

中文摘要： 闭合裂纹是金属疲劳损伤的早期表现形式之一，因其界面相互接触导致常规无损检测方法从检测效果和工程应用前景来说均不理想。 本课题提出利用涡流加载改变金属闭合裂纹状态，实现对经过该区域的超声波的可控调制,以提高缺陷检测的灵敏度和可信度。拟建立金属闭合裂纹涡流激励的电磁-力-形变耦合模型，计算不同加载条件下裂纹区的电磁场、应力与形变分布，研究基于洛仑兹力的金属闭合裂纹波动机制,分析加载过程中闭合裂纹的动态特性及其对超声非线性响应的影响，阐明电磁加载下裂纹的超声调制机理，通过分析经调制的超声回波，研究电磁加载下闭合裂纹引起的超声非线性现象，论证该方法对闭合裂纹定量检测的可行性，为金属疲劳损伤早期诊断提供理论依据。 与传统非线性超声检测不同，该方法是由于洛伦兹力的存在导致超声波与闭合裂纹界面相互作用时产生的声波调制现象，通过改变电磁加载参数可一定程度上调节裂纹面的波动状态,使超声波的被调制过程可控。

中文关键词： 电磁加载；动态特性；数值分析；非线性超声；调制机理

英文摘要： Closed-crack is one of the early form of the metal fatigue damage. Because of the contact surface of the closed-crack, the detection performance and prospect of engineering application of the common nondestructive testing method are not ideal. The state of the metal colsed-crack will be changed by the eddy current loading in this work. The ultrasonic will be modulated in the crack area. Through building the electromagnetism-force-deformation coupling model of the eddy current exciting, the electromagnetic field, stress and deformation in the crack area will be calculated and the dynamic mechanism of the crack will be researched based on the Lorentz force. Through analysis the dynamic behaviour of the closed-crack and the impact of the ultrasonic nonlinear response during the electromagnetic loading, it will explain the modulation mechanism of the crack in the electromagnetic loading. It will study the ultrasonic nonlinear phenonmena with the eddy current loading by analysis the modulated ultrasonic echo and demonstrate the feasibility of the quantitive detection of the crack which can provide the theory basis for early diagnosis of the metal structural damage. Different from the traditional nonlinear ultrasonic technique, the ultrasonic is modulated by the interactions between the ultrasonic wave and surface flu

英文关键词： Electromagnetic loading；Dynamic behaviour；Numerical analysis；Nonlinear ultrasonic；Modulation mechanism