Numerical simulation of flexible ultrasonic technology for detection of internal defects in cable sealing layer

The lead sealing layer has an important sealing and waterproofing role in various terminal joints and intermediate connections of the metal lead sheath of the cable. In this paper, the finite element analysis method is used to investigate the detection and localisation effect of array ultrasonic technology in the simulation of cable lead sealing layer defects. In COMSOL Multiphysics software to build a two-dimensional cable structure model containing different sizes of sealing layer defects, the establishment of "acoustic-thermal-solid mechanics" multi-physical field coupling model, to achieve the acoustic field inside the cable terminals, the coupling effect of thermal field and solid mechanics, simulated ultrasonic propagation characteristics of the cable structure, and analysed the detection and location of defects in the cable. The propagation characteristics of ultrasonic wave in the cable structure are simulated, and the echo signals received at the detection point are analysed to achieve the detection and positioning of sealing defects. By analysing and simulating typical defects, the results show that there is a significant difference between the echo signals received at the detection point of a defective sealing layer and a non-defective sealing layer.