Study on the determination method of excitation load in electrical signal simulation for piezoelectric ultrasonic internal inspection of pipelines.

Accurately determining the initial acoustic field excitation load of a piezoelectric ultrasonic probe is essential for simulating electrical signals and calculating wall thickness during ultrasonic internal inspection of pipelines. A new method for determining the initial excitation load of the acoustic field is proposed, incorporating the focusing effect of the curved surface of pipelines on the ultrasonic signal from the piezoelectric ultrasonic probe. Finite element models were established for the new and old methods using COMSOL software, facilitating the analysis of the initial acoustic field distribution and associated electrical signal characteristics. Scenarios considered included pipelines with and without inner wall defects, and with or without a deviation angle between the pipeline and the probe. The pipeline wall thickness was calculated inversely for each condition. Comparisons with actual wall thickness revealed that the initial excitation load determined by the new method significantly improved accuracy in wall thickness inversion, compared to the published existing method. This indicates that considering the focusing effect of the curved surface of pipelines on ultrasonic signals enhances the accuracy of simulation for piezoelectric ultrasonic internal inspection. This lays the groundwork for developing a digital research and development platform tailored for the ultrasonic internal detectors of pipeline.