Simulation and algorithmic implementation of ultrasonic phased-array imaging for curved lead-seal surfaces

Jian Cheng
China Southern Power Grid Shenzhen Power Supply Bureau Co., Ltd., Shenzhen 518001, China
Liguang Hu
China Southern Power Grid Shenzhen Power Supply Bureau Co., Ltd., Shenzhen 518001, China
Fengyin Zhang
China Southern Power Grid Shenzhen Power Supply Bureau Co., Ltd., Shenzhen 518001, China
Quan Zhang
China Southern Power Grid Shenzhen Power Supply Bureau Co., Ltd., Shenzhen 518001, China
Lianbing Wang
China Southern Power Grid Shenzhen Power Supply Bureau Co., Ltd., Shenzhen 518001, China

Article ID: 4152

Keywords: high-voltage cable termination; curved lead-seal surface; phased-array ultrasonic testing; delay-and-sum imaging; angular correction; defect localization

Abstract

In ultrasonic phased-array sector scanning of lead-seal defects in high-voltage cable terminations, incomplete contact between the probe and the curved lead-seal surface may cause acoustic-beam spreading, focal shift, weak defect echoes, image distortion, and near-surface artefacts. To address these problems, this study proposes a curvature-adaptive ultrasonic phased-array imaging method for curved lead-seal surfaces. First, an acoustic-field simulation model of the curved lead-seal structure was established to analyze beam propagation through the couplant layer and the lead seal. Then, a delay law based on Fermat’s principle and Snell’s law was derived to account for the curved interface and the two-layer propagation path. The calculated delays were applied during post-processing delay-and-sum beam synthesis, followed by Hilbert-envelope extraction and angular coordinate correction. Numerical results show that the curved interface causes beam spreading and focal-position shift compared with a flat interface, which explains the localization deviation in conventional phased-array imaging. Laboratory experiments were further conducted on lead-seal specimens with internal defects, interlayer defects, and combined internal–interlayer defects. For the internal defect with an actual depth of 15.0 mm, the positioning error was reduced from 13.33% to 6.67%. For the interlayer defect with an actual depth of 25.0 mm, the positioning error was reduced from 10.00% to 4.00%. The results demonstrate that the proposed method improves defect localization accuracy, morphology restoration, and imaging consistency compared with conventional phased-array imaging. This study provides a simulation-supported and experimentally validated method for curved lead-seal ultrasonic imaging, although further validation is still required for naturally formed irregular cracks, variable coupling conditions, and field cable-terminal applications.

Published

2026-07-27

How to Cite

Cheng, J., Hu, L., Zhang, F., Zhang, Q., & Wang, L. (2026). Simulation and algorithmic implementation of ultrasonic phased-array imaging for curved lead-seal surfaces. Sound & Vibration, 60(5). https://doi.org/10.59400/sv4152

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Vol. 60 No. 5 (2026): In Progress

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Article

This work is licensed under a Creative Commons Attribution 4.0 International License.

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