The water-lubricated thrust bearings of the marine rim-driven thruster(RDT)are usually composed of polymer composites,which are prone to serious wear under harsh working conditions.Ultrasonic is an excellent non-destr...The water-lubricated thrust bearings of the marine rim-driven thruster(RDT)are usually composed of polymer composites,which are prone to serious wear under harsh working conditions.Ultrasonic is an excellent non-destructive monitoring technology,but polymer materials are characterized by viscoelasticity,heterogeneity,and large acoustic attenuation,making it challenging to extract ultrasonic echo signals.Therefore,this paper proposes a wear monitoring method based on the amplitude spectrum of the ultrasonic reflection coefficient.The effects of bearing parameters,objective function,and algorithm parameters on the identification results are simulated and analyzed.Taking the correlation coefficient and root mean square error as the matching parameters,the thickness,sound velocity,density,and attenuation factor of the bearing are inversed simultaneously by utilizing the differential evolution algorithm(DEA),and the wear measurement system is constructed.In order to verify the identification accuracy of this method,an accelerated wear test under heavy load was executed on a multi-functional vertical water lubrication test rig with poly-ether-etherketone(PEEK)fixed pad and stainless-steel thrust collar as the object.The thickness of pad was measured using the high-precision spiral micrometer and ultrasonic testing system,respectively.Ultimately,the results demonstrate that the thickness identification error of this method is approximately 1%,and in-situ monitoring ability will be realized in the future,which is of great significance to the life prediction of bearings.展开更多
Water-lubricated bearing has become the development trend in the future because of its economy and environmental friendliness.The poor friction performance under low speed and heavy load seriously limits the populariz...Water-lubricated bearing has become the development trend in the future because of its economy and environmental friendliness.The poor friction performance under low speed and heavy load seriously limits the popularization and application of water-lubricated bearings.Learning from nature,the phenomenon of low friction and wear in nature has aroused great interest of scientists,and a lot of research has been carried out from mechanism analysis to bionic application.In this review,our purpose is to provide guiding methods and analysis basis for the bionic design and theoretical research of anti-friction and anti-wear of water-lubricated bearings.The development of water-lubricated bearing materials are described.Some typical examples of natural friction reduction and drag reduction are introduced in detail,and several representative preparation methods are listed.Finally,the application status of bionic tribology in water-lubricated bearings is summarized,and the future development direction of water-lubricated bearings is prospected.展开更多
基金supported by the National Key R&D Program of China(No.2018YFE0197600)European Union’s Horizon 2020 Research and Innovation Programme RISE under Grant Agreement No.823759(REMESH)the National Natural Science Foundation of China(No.52071244).
文摘The water-lubricated thrust bearings of the marine rim-driven thruster(RDT)are usually composed of polymer composites,which are prone to serious wear under harsh working conditions.Ultrasonic is an excellent non-destructive monitoring technology,but polymer materials are characterized by viscoelasticity,heterogeneity,and large acoustic attenuation,making it challenging to extract ultrasonic echo signals.Therefore,this paper proposes a wear monitoring method based on the amplitude spectrum of the ultrasonic reflection coefficient.The effects of bearing parameters,objective function,and algorithm parameters on the identification results are simulated and analyzed.Taking the correlation coefficient and root mean square error as the matching parameters,the thickness,sound velocity,density,and attenuation factor of the bearing are inversed simultaneously by utilizing the differential evolution algorithm(DEA),and the wear measurement system is constructed.In order to verify the identification accuracy of this method,an accelerated wear test under heavy load was executed on a multi-functional vertical water lubrication test rig with poly-ether-etherketone(PEEK)fixed pad and stainless-steel thrust collar as the object.The thickness of pad was measured using the high-precision spiral micrometer and ultrasonic testing system,respectively.Ultimately,the results demonstrate that the thickness identification error of this method is approximately 1%,and in-situ monitoring ability will be realized in the future,which is of great significance to the life prediction of bearings.
基金the National Natural Science Foundation of China(Grant no.52171319).
文摘Water-lubricated bearing has become the development trend in the future because of its economy and environmental friendliness.The poor friction performance under low speed and heavy load seriously limits the popularization and application of water-lubricated bearings.Learning from nature,the phenomenon of low friction and wear in nature has aroused great interest of scientists,and a lot of research has been carried out from mechanism analysis to bionic application.In this review,our purpose is to provide guiding methods and analysis basis for the bionic design and theoretical research of anti-friction and anti-wear of water-lubricated bearings.The development of water-lubricated bearing materials are described.Some typical examples of natural friction reduction and drag reduction are introduced in detail,and several representative preparation methods are listed.Finally,the application status of bionic tribology in water-lubricated bearings is summarized,and the future development direction of water-lubricated bearings is prospected.
