基于磁致伸缩效应的换热管导波振动检测理论与方法研究

项目名称： 基于磁致伸缩效应的换热管导波振动检测理论与方法研究

项目编号： No.51205148

项目类型： 青年科学基金项目

立项/批准年度： 2013

项目学科： 机械工程学科

项目作者： 徐江

作者单位： 华中科技大学

项目金额： 25万元

中文摘要： 随着石化、核电等重大工程的实施，如何在检修期间实现大量换热管的快速检测是一个难题。虽然导波检测技术能够实现换热管的快速检测，但无法满足检测精度要求。针对换热管长度有限这一特点，本项目以磁致伸缩导波激励下换热管稳态振动形成和衰减过程中观察到的新现象为基础，提出换热管磁致伸缩导波振动检测方法，其特色在于激励信号频率大于10kHz，周期数达几千个，足以让换热管达到稳态振动。通过研究换热管磁致伸缩导波激励下稳态振动形成和衰减过程中的时频特性，建立缺陷与振动响应之间的联系，探寻一种换热管高精度检测方法。主要研究内容包括长时导波激励下有限长空心圆柱体的振动特性、导波激励下有限长空心圆柱体振动的零状态和零输入响应模型、缺陷在零状态和零输入响应过程中的表征及其规律、以实验和仿真信号为基础提取缺陷特征的信号处理方法。本项目的研究成果将为导波检测提供一种新思路。

中文关键词： 换热管；振动；导波；磁致伸缩效应；无损检测

英文摘要： With the implementation of the petrochemical, nuclear and other key projects, how to detect a large number of heat exchanger tubes quickly and accurately during the shutdown period is a problem. The guided wave testing method can be applied to detect the tubes quickly, but the detecting precision cannot meet the requirements. As the length of the heat exchange tube is finite, the magnetostrictive guided wave vibration method is proposed based on the new phenomena observed in the formation and attenuation of the steady-state vibration with the magnetostrictive guided wave excitation. In this method, the excitation frequency is greater than 10 kHz. And the number of cycles of the excitation is several thousands which make finite length heat exchanger tubes to the steady vibration. The time- frequency characteristics in the formation and attenuation process of the steady-state vibration with the magnetostrictive guided wave excitation is studied and the relation between the defects and the vibration response is established to explore a high precision testing method for the heat exchanger tubes. The main works includes: studying vibration characteristics of the finite length hollow cylinder under the long time guided wave excitation; establishing the model of the zero-state response and the zero-input response of th

英文关键词： heat exchange tube；vibration；guided wave；magnetostrictive effect;；nondestructive testing