桥梁缆索断丝微磁检测技术研究

RESEARCH ON BROKEN WIRES DETECTION OF BRIDGE CABLES BY MICRO-MAGNETIC MEASUREMENT TECHNOLOGY

基于铁磁材料的剩磁现象,建立了桥梁缆索断丝缺陷漏磁场分析有限元模型,分析了断口处钢丝表面及空气中的漏磁场分布规律,计算了空气层中漏磁场的强度,为微磁探伤技术的应用提供了理论依据;搭建了基于微磁原理的缆索断丝检测试验平台,采用三维磁阻式传感器对缺陷缆索的模拟试件进行了探伤实验,试验结果证实了缆索钢丝中剩磁场的存在及断丝处漏磁场的可检性,分析了不同断丝数量及不同断丝位置的漏磁信号特征,验证了理论分析的正确性及微磁检测方法的可行性;基于微磁原理的缆索断丝无损检测系统,可省略笨重的激磁单元,为实现检测装置的节能化与轻量化设计提供了科学依据。

Based on remanence magnetic field of ferromagnetic materials, a finite element model for leaking magnetic field of broken wire of bridge cables was established. Using this model the magnetic field distribution of fracture surface of the wire and the air leak were analyzed, the leaking magnetic field strength was calculated. At the same time, a testing platform of broken wire of cables by using three-dimensional magnetoresistive sensor was build. Experimental results confirmed the existence of leakage magnetic field of broken wire and it can be detected. The leakage magnetic flux signal characteristics varies from different number and different locations of broken wire, which verify the correctness, effectiveness and feasibility of micro-magnetic detection methods.