Parametric Analysis of Weld Defects in Orthotropic Steel Bridge Deck Based on Eddy Current Excitation Method

Orthotropic steel bridge decks are widely used in various types of bridges, and defects in their welded parts are the object of monitoring and detection in the bridge manufacturing and operation, and maintenance phases. Considering the structural characteristics of orthotropic steel bridge decks, the characteristics of the application scenarios, and the geometric and physical properties of the defects, this study simulates and theoretically analyses the values of the main parameters used in the eddy current excitation method. Firstly, based on the eddy current excitation theory, the magnetic field distribution law of the basic specimen was analyzed in the frequency domain, and eddy current calculations were carried out for the local discretisation of the specimen with defects. Secondly, a multi-field coupled analysis software is used to simulate the eddy current magnetic field excited by the coil to derive the conduction current density and magnetic vector potential of the orthotropic steel bridge deck. The results show that the method can be used for non-destructive testing of weld defects in open orthotropic steel bridge decks. Still, for closed and internal defects, the method is not satisfactory, and needs to be used in conjunction with other testing methods to make a comprehensive judgement of the damage information.