【作者】 郭鹏；

【导师】 史荣；

【作者基本信息】 燕山大学 ， 机械设计及理论， 2012， 硕士

【摘要】 钢丝绳缺陷的弱磁检测技术，是指将钢丝绳磁化到其最大磁导率点左侧时，通过检测缺陷处的漏磁场来实现探伤。弱磁检测技术的特点在于检测速度快、传感器灵敏度高、有望实现在线监测，是电磁探伤领域的最新技术之一，也是目前世界各国研究的热点问题之一。本文在分析比较现有钢丝绳探伤方法优缺点的基础上，提出了弱磁检测方案，并对其进行了深入的理论分析与大量的试验研究，证实了钢丝绳缺陷弱磁检测方法的可行性。依据磁荷分析理论，建立了磁偶极子模型，利用磁路磁导法设计了基于弱磁探伤的钢丝绳无损探伤实验平台主要参数，搭建了基于虚拟仪器的实验平台，编制了基于LabVIEW2010的数据采集程序，在该实验平台上，对Φ8mm、Φ30mm，规格均为6X19S+SF的具有不同断丝缺陷的钢丝绳进行了探伤，得到了与缺陷相对应的实测曲线，验证了弱磁检测技术的可行性。在正交试验理论指导下，设计了磁路系统参数的三因素四水平正交实验表，探索了各因素不同水平的组合对检测结果的影响，并最终的得出了对被测钢丝绳而言的最佳磁路系统参数。采用小波分析技术，在LabVIEW2010软件平台下调用Matlab，编制了小波分析程序。采用幅值超门限算法实现了缺陷段数据的有效提取，通过对缺陷段数据峰峰值的提取结合磁偶极子理论初步计算了缺陷处断丝的数量，并根据钢丝绳的报废准则断定了钢丝绳是否能够继续使用。为了实现测试系统数据采集与处理的一体化，用LabVIEW2010软件编写了一套集探伤数据采集、读取、分析于一体的钢丝绳无损探伤界面，用户只需要进行简单的操作便可实现自动记录、自动分析、形成实验报告等功能。通过对具有疲劳断丝的Φ25.4mm报废钢丝绳进行检测，进一步证实了弱磁检测技术的可行性与测试结果的可靠性。本文的研究成果为测试仪器的设计提供了科学依据。更多还原

【Abstract】 The weak magnetic inspection of wire ropes flaw is to detect the leakage magneticfield in the defects when the wire rope is magnetized to the left of the maximumpermeability point. The characteristics of weak magnetic inspection are high detectionspeed and high sensitivity of sensor. It is possible to make monitoring on reality. It is oneof the latest techonology in the field of magnetic testing and a hot topic in the world.Basedon the analysis of advantages and disadvantags of the existing methods of wire ropestesting, this paper presents a weak magnetic inspection program. In order to confirm thefeasibility of the method, some theoretical analysis and a great deal of experimentialstudies are done in this paper.According to the theory of analysis of magnetic charge, the magnetic dipole modelsare built. Based on the weak magnetic inspection，the method of magnetic circuit magneticpermeability is adopted to calculated the parameters of the experimental platform for wireropes nondestructive testing. The experimental platform based on virtual instrument isbuilt, the program for data acquisition is compiled. On the platform,the wire ropes withmany broken wires whose diameters are30mm and8mm and specification is6×19S+SFare detected. The measured curves which are identical with defects are acquired. Theresults further demonstrate the feasibility of weak magnetic detection technology.According to the theory of orthogonal experiment, the orthonogal test table L16wasused to study the impact on the test result when the experimental factors are in differentlevels. The best parameters of magnetic circuit system are obtained for the testing wireropes.Based on wavelet analysis technique, the program for data analysis is written bycalling Matlab in LabVIEW with Matlab script node. In order to extract the abnormal dataeffectively, the amplitude super threshold algorithm is used to analyze result files.According to the theory of magnetic dipole, by extracting the peak to peak value, thenumber of broken wires is calculated. By camparing the results and scrap standard of wireropes, whether the wire rope should be replaced is determined.In order to make the data acquisition and processing done by a test system, an interface for wire ropes NDT is written based on LabVIEW2010. It includes dataacquisition, reading and analysis. It can record and analyze data, form experimentalreport and other function with some simple operation.The feasibility of weak magnetic inspection and the reliability of test result areproved further by inspecting a scrap wire rope with some fatigue broken wires whosediameter is25.4mm. The research achievement provides in this paper some scientific basisfor the design of the testing instrument.更多还原