The influence of coupling layer thickness on hollow axles ultrasonic testing

Abstract

The thickness of coupling layer between the hollow axle inner wall and the probe wedge may vary during actual ultrasonic inspection. To study the influence of coupling layer thickness on the hollow ultrasonic inspection, the simulation models with different probe angles and different thicknesses of coupling layer were established with COMSOL Multiphysics. Flaw echoes from 38° and 45° probes under various coupling thickness were calculated and analyzed in details. A special experimental system was designed to validate the simulation results. Both simulation and experiment show that the coupling thickness variation may impact the reliability of ultrasonic testing results when the coupling thickness is less than 0.9mm.