建筑钢结构磁记忆检测仪的关键技术研究

发布时间：2018-02-28 16:40

本文关键词： 建筑钢结构磁记忆检测仪关键技术影响因素表征磁敏探头　出处：《西安建筑科技大学》2014年硕士论文　论文类型：学位论文

【摘要】：金属磁记忆(MMM)检测技术可以对铁磁构件进行早期损伤检测，一经问世，便得到了世界各地科研人员的普遍关注。由于各行业的特殊性与不同性，各种专用磁记忆检测仪应运而生。但这些检测仪仅能发现早期损伤位置，未给出应力与磁记忆信号之间的对应关系，无法及时判断构件破坏前的临界状态。因而，只能用以危险区域位置的初步判断，难以真正实现建筑结构早期预警的目的。同时，金属磁记忆检测技术在建筑钢结构领域尚处于起步阶段，无专用磁记忆检测仪问世。本文将这种新型的无损检测技术与钢结构相结合，对建筑钢结构专用磁记忆检测仪实现过程中的几个关键技术问题做了深入研究，主要进行了以下工作：（1）通过理论及试验研究，分析了不同的初始磁场、不同的提离高度、在线与离线检测、不同检测方向等外界因素对磁记忆信号的影响。对建筑钢结构检测仪有针对性的提出了一定改进措施，，这是检测仪开发首先要解决的关键技术问题。（2）通过对Q345B钢材展开拉伸与弯曲试验，研究了适用于建筑钢结构磁记忆检测仪的应力表征参数，表征参数的选取与设置是钢结构磁记忆检测仪的核心关键技术问题。结果表明：轴向拉伸作用下，磁场梯度曲线峰值与应力有较强的指数关系，梯度峰值可用于表征轴向拉伸荷载作用下构件的应力发展状况；~曲线在屈服应力附近出现最大值，其峰值点处的应力可用于表征拉伸荷载下试件的屈服应力。弯曲荷载作用下，磁记忆曲线在试件顶部和底部均出现“单峰”现象，可通过磁记忆曲线峰值区域来判断构件的应力集中区；受弯构件底部的|H mp|~曲线在屈服应力附近迅速增长并出现“分界点”，可利用“分界点”处的应力表征受弯构件受拉边的屈服应力。（3）分析了适用于钢结构磁记忆检测仪的电子元件和电路选择的问题，这是专用检测仪实现需要解决的最直接技术问题。磁敏探头是检测仪的核心，霍尔元件或磁敏二极管形成的探头更适用于建筑钢结构磁记忆检测仪。针对建筑钢结构特殊性，提出了合适的滤波、放大、A/D转换、处理器选择的建议。
[Abstract]:Metal magnetic memory (MMM) detection technology can be used in early detection of damage of ferromagnetic components, by the advent of has obtained the widespread attention of researchers around the world. Because of the particularity of the industry and sex, appeared many kinds of special magnetic memory testing instrument. But the detector can only detect the early damage location, not given the correspondence between strain and magnetic memory signal, unable to determine the critical state components before failure in time. Therefore, only to determine the initial position in dangerous areas, it is difficult to realize the construction of early warning. At the same time, metal magnetic memory testing technology is still in its infancy in the field of building steel structure, no special magnetic memory the advent of detector. In this paper the new nondestructive testing technology and steel structure combination of several key technical problems in the process of building steel structure special magnetic memory testing instrument In depth research, the following work has been carried out.
(1) through theoretical and experimental research, analysis of the initial magnetic field is different, different lift off height, online and offline detection, detection of external factors such as the effect of different directions of the magnetic memory signal. The construction steel structure tester and puts forward some improvement measures, this is the key technical problems of developing instrument the first to solve.
(2) through the tensile and Flexural Tests of Q345B steel were studied for building steel structure and magnetic memory testing instrument of stress parameters, parameter selection and setting is the key technology of steel structure magnetic memory testing instrument. The results show that the axial tensile loads, the magnetic field gradient curve peak has exponential relationship strong and stress gradient component values can be used in the characterization of axial tensile stress development; ~ curve in the yield stress near the maximum value of the peak point of the stress can be used to characterize the tensile specimen under yield stress. Under bending load, the magnetic memory curve top and at the bottom of the "single peak" phenomenon appeared in the trial, the magnetic memory curve peak area to determine the component of the stress concentration area is at the bottom; the bending of |H mp|~ curve in the yield stress near the rapid growth and the emergence of The "demarcation point" can be used to characterize the yield stress at the edge of the flexural member by the stress at the "demarcation point".
(3) analysis of the electronic components and circuits suitable for steel structure magnetic memory testing instrument selection problem, which is the most direct to solve the technical problems of implementation of the special detecting instrument. The magnetic sensing probe is the core of the instrument, Holzer probe element or magneto diode formation is more suitable for the construction of steel structure of magnetic memory testing instrument. According to the particularity of construction steel structure, puts forward the appropriate filtering, amplification, A/D conversion, processor options.

【学位授予单位】：西安建筑科技大学
【学位级别】：硕士
【学位授予年份】：2014
【分类号】：TU391;TU317

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