ABSTRACT

The metal magnetic memory is used to detect the micro damage of structure based on the SMFL (self-magnetic flux leakage) effect, but it lacks an effective comprehensive diagnosis index suitable for the ferromagnetic material. In this paper, steel strand specimens were tensioned at different force levels, and the experimental study on the corrosion detection was carried out. Besides the monitoring analysis of the cable force, the initial structural magnetic field ΔB_x0 and the surface SMFL signals B_x(α) induced by corrosion were both analysed. The results show that ΔB_x0 curves of steel strand material present the periodic fluctuation. Considering ΔB_x0 and measuring distance z, the proposed dimensionless damage analysis index X can be used for the quantitative research of corrosion diagnosis. The small influence of the cable force on index X is also illustrated. Moreover, the strong correlation that exists between the average maximum index $\overline{{\mathrm{X}}_{\mathrm{m}\mathrm{a}\mathrm{x}}}$ and the corrosion ratio α is well fitted by the three-order polynomial curves.

摘要

金属磁存储器用于基于SMFL（自漏磁）效应检测结构的微观损伤，但缺乏适用于铁磁材料的有效综合诊断指标。本文对钢绞线试样在不同的受力水平下张拉，并进行了腐蚀检测的实验研究。除了对索力的监测分析外，还分析了由腐蚀引起的初始结构磁场ΔB _{x 0}和表面SMFL信号B _x ( α )。结果表明，钢绞线材料的ΔB×0曲线呈现周期性_波动。考虑到ΔB_{x 0}和测量距离z，所提出的无量纲损伤分析指标X可用于腐蚀诊断的定量研究。还说明了索力对指数X的微小影响。此外，平均最大指数之间存在强相关性$\overline{{\mathrm{X}}_{\mathrm{米}\mathrm{一个}\mathrm{X}}}$三阶多项式曲线很好地拟合了腐蚀率α 。