The effect of surface structure and coating on tribological properties of 45^# carbon steel disc was analyzed. A Nd：YAG laser was used to generate rnicrodirnples on steel surfaces. Dimples with diameter of 150 rn and...The effect of surface structure and coating on tribological properties of 45^# carbon steel disc was analyzed. A Nd：YAG laser was used to generate rnicrodirnples on steel surfaces. Dimples with diameter of 150 rn and depth of 50 rn were distributed in an orbicular array on disc surface. Then the alloying element Mo was sputtered to 45# carbon steel disc surface by means of double glow plasma technology. Diffusion Mo alloying layer with 30min thickness and high hardness up to 0.025 was formed on the disc surface. Tribological experiments of three types samples （smooth, texturing and texturing＋alloying） were conducted with a pin-on-disc tribometer. It is found that the dimpled-samples are most effective for reducing friction in comparison with smooth steel surthces, improving the lubricating state from boundary to hydrodynamic region.展开更多
There is still a lack of effective lubrication condition monitoring methods in the field of diesel engines.The paper proposes a novel thermoelectric approach to divide the lubrication state of bearings.First,the gener...There is still a lack of effective lubrication condition monitoring methods in the field of diesel engines.The paper proposes a novel thermoelectric approach to divide the lubrication state of bearings.First,the generation mechanism of thermoelectric potential on bearings is clarified.Then,both experimental and simulation studies are done,and a strong correlation between lubrication and thermoelectric potential is shown.The film thickness and temperature are further confirmed as significant factors influencing thermoelectric potential.Generally,the thermoelectric potential increases with temperature.However,a small film thickness ratio(when the film thickness ratio is less than 4)will suppress the thermoelectric potential.Three typical lubrication states of bearings are distinguished through thermoelectric potential and supported by the Stribeck curve results.Moreover,the significant influence of lubrication on the bearing is confirmed through the analysis of surface morphology and composition.展开更多
The surface-initiated Rolling Contact Fatigue(RCF)including pitting and micro-pitting is one of the key issues affecting the reliability of tribological components such as gears and bearings used in various devices.In...The surface-initiated Rolling Contact Fatigue(RCF)including pitting and micro-pitting is one of the key issues affecting the reliability of tribological components such as gears and bearings used in various devices.In this work,a surface-initiated crack Finite Element(FE)model which considers the effect of lubricant on crack faces was developed to investigate surface-initiated RCF using an automatic crack propagating Python script.Different lubricating states,initial crack parameters and loading conditions were simulated to analyze the evolution of crack propagation and the Stress Intensity Factors(SIFs).The RCF crack propagation path and life were predicted by employing the Maximum Tangential Stress(MTS)criterion coupled with the Paris’s law.A typical RCF failure is predicted in the numerical simulation.Results reveal that the lubricating pressurization dominates the surface-initiated RCF.In addition,the initial crack angle has a significant effect on the RCF crack propagation path and the fatigue life.展开更多
基金Funded by the High Technology Research Project of Jiangsu Province (No. BG2007046)the Productive Translation Item of College Scientific Research of Jiangsu Province Educational Office( No. JHB06-04)
文摘The effect of surface structure and coating on tribological properties of 45^# carbon steel disc was analyzed. A Nd：YAG laser was used to generate rnicrodirnples on steel surfaces. Dimples with diameter of 150 rn and depth of 50 rn were distributed in an orbicular array on disc surface. Then the alloying element Mo was sputtered to 45# carbon steel disc surface by means of double glow plasma technology. Diffusion Mo alloying layer with 30min thickness and high hardness up to 0.025 was formed on the disc surface. Tribological experiments of three types samples （smooth, texturing and texturing＋alloying） were conducted with a pin-on-disc tribometer. It is found that the dimpled-samples are most effective for reducing friction in comparison with smooth steel surthces, improving the lubricating state from boundary to hydrodynamic region.
基金supported by Shanghai Municipal Natural Science Foundation(No.22ZR1430600).
文摘There is still a lack of effective lubrication condition monitoring methods in the field of diesel engines.The paper proposes a novel thermoelectric approach to divide the lubrication state of bearings.First,the generation mechanism of thermoelectric potential on bearings is clarified.Then,both experimental and simulation studies are done,and a strong correlation between lubrication and thermoelectric potential is shown.The film thickness and temperature are further confirmed as significant factors influencing thermoelectric potential.Generally,the thermoelectric potential increases with temperature.However,a small film thickness ratio(when the film thickness ratio is less than 4)will suppress the thermoelectric potential.Three typical lubrication states of bearings are distinguished through thermoelectric potential and supported by the Stribeck curve results.Moreover,the significant influence of lubrication on the bearing is confirmed through the analysis of surface morphology and composition.
基金supported by the National Key R&D Program of China(No.2018YFB2001300)。
文摘The surface-initiated Rolling Contact Fatigue(RCF)including pitting and micro-pitting is one of the key issues affecting the reliability of tribological components such as gears and bearings used in various devices.In this work,a surface-initiated crack Finite Element(FE)model which considers the effect of lubricant on crack faces was developed to investigate surface-initiated RCF using an automatic crack propagating Python script.Different lubricating states,initial crack parameters and loading conditions were simulated to analyze the evolution of crack propagation and the Stress Intensity Factors(SIFs).The RCF crack propagation path and life were predicted by employing the Maximum Tangential Stress(MTS)criterion coupled with the Paris’s law.A typical RCF failure is predicted in the numerical simulation.Results reveal that the lubricating pressurization dominates the surface-initiated RCF.In addition,the initial crack angle has a significant effect on the RCF crack propagation path and the fatigue life.
