基于自发漏磁效应的钢丝束多点断丝损伤检测研究

Multi-point Wire Bundle Breakage Damage Detection Based on Self-magnetic Leakage Effect

斜拉索的完整性对斜拉桥的服役安全至关重要。针对斜拉索突出的断丝损伤问题,本工作利用37根钢丝排列组成平行钢丝束模拟拉索试件,设置了不同工况模拟拉索的断丝状态,分析漏磁信号曲线变化特征并构建了特征指标(B_(sd))以定量评估拉索的断丝损伤程度。结果表明:不同断丝率下磁感应强度法向分量(B_(z))曲线两极值间水平间距与断丝宽度呈良好的线性正相关,且极值间距的变化对断丝率的影响不敏感;磁感应强度切向分量(B_(x))、B_(z)值在相同断丝宽度、不同断丝率条件下的增量比在相同断丝率、不同断丝宽度条件下的增量大,说明漏磁信号受断丝率的影响更大;采用二次多项式可以较好地拟合断丝宽度、断丝率与特征指标之间的相关性,不同影响因素与指标的拟合优度均大于0.95;随断丝宽度和断丝率的增加,拟合曲线与曲面的斜率都逐渐减小;通过特征指标在不同影响因素下的增量分析,验证了断丝率对漏磁信号的影响大于断丝宽度。

The integrity of cable-staying is crucial to the service safety of cable-stayed bridges.To address the prominent wire breakage damage problem,this work used 37 wires arranged into parallel wire bundles to simulate cable-stayed specimens.Different working conditions were set up to simulate the wire breakage state,the changing characteristics of the leakage signal curves were analyzed and the characteristic index B_(sd) was constructed to quantitatively evaluate the wire breakage damage.The results showed that the two polar spacings of B_(z) curves at different wire breakage rates were well linearly and positively correlated with the wire breakage width,the change of polar spacing was insensitive to the wire breakage rate.The increments of the values of B_(x) and B_(z) at the same wire breakage width with different wire breakage rates were larger than those at the same wire breakage rate with different wire breakage widths,indicating the signal was more influenced by the wire breakage rate.The correlation between the wire breakage width,wire breakage rate and the index can be fitted better by using quadratic polynomial,and the goodness of fit of different influencing factors and the index is greater than 0.95.The slope of the fitted curves decreases gradually with the increase of the wire breakage width and the wire breakage rate.Through the analysis of the increment of the index under different factors,it is verified that the influence of the wire breakage rate on the signal is greater than that of the wire breakage width.