With the development of green tribology in the shipping industry,the application of water lubrication gradually replaces oil lubrication in stern bearings and thrust bearings.In terms of large-scale and high-speed shi...With the development of green tribology in the shipping industry,the application of water lubrication gradually replaces oil lubrication in stern bearings and thrust bearings.In terms of large-scale and high-speed ships,water-lubricated bearings with high performance are more strictly required.However,due to the lubricating medium,water-lubricated bearings have many problems such as friction,wear,vibration,noise,etc.This review focuses on the performance of marine water-lubricated bearings and their failure prevention mechanism.Furthermore,the research of marine water-lubricated bearings is reviewed by discussing its lubrication principle,test technology,friction and wear mechanism,and friction noise generation mechanism.The performance enhancement methods have been overviewed from structure optimization and material modification.Finally,the potential problems and the perspective of water-lubricated bearings are given in detail.展开更多
Several soft tissues residing in the living body have excellent hydration lubrication properties and can provide effective protection during relative motion.In order to apply this advantage of soft matters in practica...Several soft tissues residing in the living body have excellent hydration lubrication properties and can provide effective protection during relative motion.In order to apply this advantage of soft matters in practical applications and try to avoid its disadvantage,such as swelling and weakening in water,a design strategy of a soft/hard double network(DN)hydrogel microsphere modified ultrahigh molecular weight polyethylene(UHMWPE)composite is proposed in this study.A series of microspheres of urea-formaldehyde(UF),polyacrylamide(PAAm)hydrogel,UF/PAAm double network,and their composites were prepared.The mechanical properties,swelling,wettability,friction properties,and the lubrication mechanisms of the composites were investigated.The results show that DN microspheres can have an excellent stability and provide hydration lubrication.The performance of 75 DN-1 composite was superior to others.This finding will provide a novel strategy for the development of water-lubricated materials and have wide application in engineering fields.展开更多
Natural materials tend to exhibit excellent performance in the engineering field because of their structure and special functions.A natural red willow,called natural porous wood material(NPWM),was found,and wear tests...Natural materials tend to exhibit excellent performance in the engineering field because of their structure and special functions.A natural red willow,called natural porous wood material(NPWM),was found,and wear tests were conducted to determine its potential as an oil-impregnated material by utilizing its special porous structure.Fluorination treatment was adopted to improve the NPWM properties for absorbing and storing lubricating oil.The different contributions of soaking and fluorination-soaking treatments on the tribological properties of NPWMs and their respective mechanism of effect were revealed.The results showed that the fluorination-soaking treatment helped absorb and store sufficient lubricating oil in the NPWM porous structure;therefore,more lubricating oil would be squeezed out and function as a tribol-film between contacting surfaces during the friction process,thus ultimately contributing to stable and smooth wear responses even under prolong friction.However,the formation of an oil-in-water emulsion,caused by the buoyancy effect,destroyed the oil films on the worn NPWM surface in a water environment,resulting in higher coefficients of friction(COFs)under water conditions than under dry friction,even after the fluorination-soaking treatment.The knowledge gained herein could not only verify the potential of NPWM as an excellent oil-impregnated material in the engineering field but also provide a new methodology for the design of artificial porous materials with stable and smooth friction processes.展开更多
基金financially supported by the National Key R&D Program of China(No.2018YFE0197600)National Natural Science Foundation of China(No.52071244).
文摘With the development of green tribology in the shipping industry,the application of water lubrication gradually replaces oil lubrication in stern bearings and thrust bearings.In terms of large-scale and high-speed ships,water-lubricated bearings with high performance are more strictly required.However,due to the lubricating medium,water-lubricated bearings have many problems such as friction,wear,vibration,noise,etc.This review focuses on the performance of marine water-lubricated bearings and their failure prevention mechanism.Furthermore,the research of marine water-lubricated bearings is reviewed by discussing its lubrication principle,test technology,friction and wear mechanism,and friction noise generation mechanism.The performance enhancement methods have been overviewed from structure optimization and material modification.Finally,the potential problems and the perspective of water-lubricated bearings are given in detail.
基金supported by the National Natural Science Foundation of China(51605248 and 51509195).
文摘Several soft tissues residing in the living body have excellent hydration lubrication properties and can provide effective protection during relative motion.In order to apply this advantage of soft matters in practical applications and try to avoid its disadvantage,such as swelling and weakening in water,a design strategy of a soft/hard double network(DN)hydrogel microsphere modified ultrahigh molecular weight polyethylene(UHMWPE)composite is proposed in this study.A series of microspheres of urea-formaldehyde(UF),polyacrylamide(PAAm)hydrogel,UF/PAAm double network,and their composites were prepared.The mechanical properties,swelling,wettability,friction properties,and the lubrication mechanisms of the composites were investigated.The results show that DN microspheres can have an excellent stability and provide hydration lubrication.The performance of 75 DN-1 composite was superior to others.This finding will provide a novel strategy for the development of water-lubricated materials and have wide application in engineering fields.
基金This work was supported by the National Natural Science Foundation of China(No.52075399)HighTech Ship Research Project of Ministry of Industry and Information Technology(No.MIIT[2019]358)the financial support from the program of China Scholarships Council(CSC.No.202006950002).
文摘Natural materials tend to exhibit excellent performance in the engineering field because of their structure and special functions.A natural red willow,called natural porous wood material(NPWM),was found,and wear tests were conducted to determine its potential as an oil-impregnated material by utilizing its special porous structure.Fluorination treatment was adopted to improve the NPWM properties for absorbing and storing lubricating oil.The different contributions of soaking and fluorination-soaking treatments on the tribological properties of NPWMs and their respective mechanism of effect were revealed.The results showed that the fluorination-soaking treatment helped absorb and store sufficient lubricating oil in the NPWM porous structure;therefore,more lubricating oil would be squeezed out and function as a tribol-film between contacting surfaces during the friction process,thus ultimately contributing to stable and smooth wear responses even under prolong friction.However,the formation of an oil-in-water emulsion,caused by the buoyancy effect,destroyed the oil films on the worn NPWM surface in a water environment,resulting in higher coefficients of friction(COFs)under water conditions than under dry friction,even after the fluorination-soaking treatment.The knowledge gained herein could not only verify the potential of NPWM as an excellent oil-impregnated material in the engineering field but also provide a new methodology for the design of artificial porous materials with stable and smooth friction processes.