Wear monitoring method of water-lubricated polymer thrust bearing based on ultrasonic reflection coefficient amplitude spectrum

Abstract The water-lubricated thrust bearings of the marine rim-driven thruster (RDT) are usually composed polymer composites, which prone to serious wear under harsh working conditions. Ultrasonic is an excellent non-destructive monitoring technology, but materials characterized by viscoelasticity, heterogeneity, and large acoustic attenuation, making it challenging extract ultrasonic echo signals. Therefore, this paper proposes a method based on amplitude spectrum reflection coefficient. effects bearing parameters, objective function, algorithm parameters identification results simulated analyzed. Taking correlation coefficient root mean square error as matching thickness, sound velocity, density, attenuation factor inversed simultaneously utilizing differential evolution (DEA), measurement system constructed. In order verify accuracy method, accelerated test heavy load was executed multi-functional vertical water lubrication rig with poly-ether-ether-ketone (PEEK) fixed pad stainless-steel collar object. thickness measured using high-precision spiral micrometer testing system, respectively. Ultimately, demonstrate that approximately 1%, in-situ ability will be realized in future, great significance life prediction bearings.