Surface Damage Detection Method for QTT Azimuthal Rail Weld Based on Electromagnetic Ultrasound Technology

The omnidirectional mobility of the $\mathbf{1 1 0 - m e t e r}$ radio telescope QTT (Qitai Radio Telescope) is based on its azimuthal wheel track, whose surface accuracy is related to the antenna’s high pointing accuracy and dynamic tracking performance. The azimuth track adopts integral welding technology. Due to the load generated when the roller passes through the track weld, the resulting impact causes contact fatigue between the track and the roller, leading to cracks, wear and other forms of damage on the weld surface. At present, the azimuth wheel rail weld surface detection are using traditional nondestructive testing methods, this paper proposes the use of electromagnetic ultrasound technology to detect QTT azimuth wheel-rail weld surface damage method. Construct a simplified azimuth wheel rail model with and without weld defects. Comprehensive use of electromagnetic ultrasound working mechanism and numerical simulation technology, magnetic flux density, displacement field waveform analysis. The results show that the method can effectively detect the damage on the weld surface of the wheel rail, which can provide an important reference for the welding research of the wheel rail of the antenna of large radio telescope.