Measurement of tube thickness using eddy current testing based on the modified integration range

As a low-cost, high-efficiency transportation method, pipelines are widely applied in petroleum, chemical, electric power and other industries. The pipeline in use are eroded by moist soil, internal electrolytes and transported medium during the working process, which unavoidably leads to cracks, corrosion, defects and other safety hazard. In this paper, a novel analytical method based on the modified integration range is proposed for thickness measurement of pipelines. According to Dodd-Deeds analytical solution, the integration range is related to the parameter of tube. Therefore, the revised integration limits are introduced to replace the original limit 0 and ∞. In addition, the quantitative relationship between the phase information of the sensor impedance and the thickness of pipe is investigated based on the proposed theoretical model, and it is found that the phase of the sensor impedance has an approximate linear relationship with the thickness. Finally, the proposed analytical method is validated by numerical simulations and experiments. The thickness of tube is deduced according to the proposed model, and the relative error is less than 7.0%.