An innovative ultrasonic layer phase method for rapid wear measurement of water-lubricated thrust bearings

Water-lubricated bearings in rim-driven thrusters are susceptible to accelerated wear under severe operating conditions. Conventional wear measurement techniques suffer from computationally inefficient and unsuitable for real-time monitoring. To address this challenge, a layer phase method (LP) and a layer amplitude method (LA) for rapid wear measurement are proposed based on the layer propagation function. Attenuation factor calibration and wear in-situ measurement experiments were conducted to verify the proposed methods. The results show that the LP achieves high accuracy with a relative error below 0.32%, whereas the LA exhibits notable fluctuations and substantial errors 2.67%. Both methods enhance recognition speed by approximately 2000 times compared to the inverse method. Furthermore, a systematic error analysis was performed. The findings reveal that the LA is significantly affected by the attenuation factor, while both methods demonstrate low measurement uncertainty. Concurrently, acoustic-structure coupling simulations indicate that as roughness increases, the error of the LP rises, as that of the LA exhibits fluctuations. In summary, the efficiency and accuracy of the LP endow it with the potential to achieve online wear monitoring, while LA presents evident limitations.