【作者】 王亚东；

【导师】 吕福在； 唐志峰；

【作者基本信息】 浙江大学 ， 机械工程， 2014， 硕士

【摘要】 钢绞线在工程中具有广泛的应用,在实际使用过程中容易出现不同程度的损伤,对钢绞线进行检测或者监测成为必然。本文以对钢绞线进行无损检测为目标,基于磁致伸缩原理,设计了纵向模态导波检测换能器,利用ABAQUS对导波在钢绞线中的传播进行模拟仿真,通过实验对结果进行验证。论文主要研究内容为:第一章,分析了课题的研究背景和意义,将磁致伸缩超声导波检测技术和传统无损检测技术进行了比较,并对比了不同导波激励方式的特点。介绍了国内外针对钢绞线进行的磁致伸缩导波检测技术的研究现状。第二章,介绍导波的基本概念,介绍磁致伸缩效应、相速度和群速度以及导波的频散、多模态和衰减等特性。利用数值方法对钢绞线的截面进行了网格划分,并基于半解析有限元方法通过使用matlab软件求解得到导波频散曲线,研究了中心直杆的波结构图,为换能器设计和导波检测研究打下理论基础。第三章,通过对钢绞线中纵波产生条件的分析,设计应用于钢绞线检测的纵向模态导波检测换能器,利用仿真软件对该结构的磁场进行了有限元分析。第四章,利用ABAQUS仿真软件对钢绞线进行建模,通过数值模拟对导波在钢绞线中的传播特性进行研究。研究了纵向模态导波检测钢绞线横向缺陷的反射特性,比较了导波在检测钢绞线外围钢丝和中心钢丝缺陷时的不同特性。第五章,搭建了磁致伸缩导波钢绞线检测平台,对钢绞线的检测进行实验研究。通过实验验证所设计换能器磁场调节可行性,并比较阵列式偏置磁体对钢绞线检测信号的影响,研究了导波检测钢绞线缺陷的可行性,根据实验结果,分别得出结论。第六章,对本文的研究内容进行了概括总结,并对课题的下一步工作和方向做了相应的展望。更多还原

【Abstract】 Steel strand has a wide application in engineering.It is easy to appear different degrees of damages in actual using process.It is inevitable for us to make health testing or monitoring of steel strand.Aiming at making health detection to steel strand,a sensor of exciting longitudinal mode guided waves was designed based on magnetostrictive effect,ABAQUS software was carried out on simulating the guided wave’s propagation in steel strand.The results were verified through experiments.The detail work is presented as follows:Chapter 1 presents the significance and background of the research,makes a comparison between the magnetostrictive guided wave technology and the traditional nondestructive testing technology,introduces the latest domestic and international research status of the steel strand which uses magnetostrictive guided wave testing technology.Chapter 2 introduces the basic concept of guided wave,including the magnetostrictive effect,the phase velocity and group velocity,the dispersion and attenuation of guided waves,the cross section of steel strand was meshed using the numerical method.Based on the semi-analytical finite element method,dispersion curves were calculated by matlab simulation and wave structure was also analyzed.The research above provides a theoretical basis for the sensor design and guided wave testing study subsequently.Chapter 3 designs a sensor which can be used in exciting longitudinal mode’s guided waves by making an analysis of the conditions to produce guided wave in steel strand.And a finite element analysis was carried on to simulating the magnetic field of this structure.Chapter 4 studied the propagation characteristics of guided wave by numerical simulation using ABAQUS software in steel strand.Defects of different lengths in steel strand were simulated.Making a contrast on the ability in detecting different steel strands while using guided waves.Chapter 5 builds a magnetostrictive guided wave’s detection system,studies the effect in steel strand detection by experiment,validates the effectiveness of the magnetic field’s adjustment,compares the detection signals of the array type bias,studies the feasibility of guided wave’s detection in steel strand defects,and gets the conclusions respectively.Chapter 6 summarizes the main work of the thesis,lists the conclusion and prospect for further research.更多还原