Analytical solution of axial detection coil for reinforced concrete based on pulsed eddy current

Reinforced concrete (RC) is favored by the construction industry because of its low cost and good stability, however, the internal reinforcement may be damaged in advance by some special conditions, and it is of great importance to use pulsed eddy current (PEC) non-destructive testing methods to carry out periodic testing of RC. In this paper, a voltage source is used as the excitation power source, the multilayer structure model is divided into several regions, the magnetic vector potential expression of each region is solved by the Green function, and the time-domain analytical solution of the coil current is obtained, which based on the decoupling of the frequency expression of the magnetic vector potential. The pulsed voltage excitation signal is passed through the Fourier series to obtain the analytical solution of the transient voltage generated in the axial pick-up coil. The simulation of Comsol model is constructed to compare the simulation data with the derived time-domain analytical solution, and the results show that the analytical solution of the shaft detection coil constructed in the article is highly accurate, which lays a theoretical foundation for the design of the detection of RC method and the sensor of PEC.