This paper reports on a measurement campaign in which the magnetomechanical response of a steel monopile is recorded during installation with a hydraulic impact hammer. By comparing impact-induced changes in the magnetic stray field of the structure to the measured strain, this effect is analysed for the first time under dynamic loading conditions on such a large scale. It is shown that the measured stray field displays an excellent correspondence with the strain in terms of frequency content and amplitude ratio for hammer blows that induce compressive strain pulses of different magnitude. Using the data, a non-contact method is developed and validated to infer the hammer-induced strains using the dynamic magnetic stray field. The proposed method can be applied during pile installations when the use of conventional strain measurement devices is challenging, e.g. in the offshore environment.

本文报道了一项测量活动，其中在安装液压冲击锤的过程中记录了钢单桩的磁机械响应。通过将结构的磁场杂散中的冲击引起的变化与测得的应变进行比较，首次在如此大的动态载荷条件下分析了这种影响。结果表明，在引起不同大小的压缩应变脉冲的锤击的频率含量和振幅比方面，测得的杂散场与应变表现出极好的对应关系。利用这些数据，开发并验证了一种非接触式方法，可以使用动态磁杂散场来推断锤击引起的应变。