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Journal of Iron and Steel Research(International) 2024年第1期31卷 215-223页

作者： Cheng Lu Wan-lin Wang Chen-yang Zhu Jie Zeng Xin-yuan Liu Hua-long Li School of Metallurgy and Environment Central South UniversityChangsha410083HunanChina National Center for International Research of Clean Metallurgy Central South UniversityChangsha410083HunanChina Institute of Research of Iron and Steel ShasteelZhangjiagang215625JiangsuChina

Typical Q235 low-carbon steel samples with different hydrogen contents(0.0004,0.0008,and 0.0013 wt.%)were prepared by adjusting the environment humidity and moisture.The effects of hydrogen on interfacial heat transfer,contact behavior,and microstructure evolution were investigated using a novel droplet solidification technique.The results revealed that when the hydrogen content increases from 0.0004 to 0.0013 wt.%,the maximum heat flux between the molten steel and cooling substrate decreases from 8.01 to 6.19 MW/m^(2),and the total heat removed in the initial 2 s reduces from 10.30 to 8.27 MJ/m^(2).Moreover,the final contact angle between the molten steel and substrate increases from 103.741°to 113.697°,and the number of pores on the droplet bottom surface increases significantly from 21 to 210 with the increase in hydrogen.The surface roughness of the droplet bottom surface increases from 20.902 to 49.181 pm.In addition,the average grain size of the droplet increases from 14.778 to 33.548 pm with the increase in the hydrogen content.The interfacial contact condition becomes worse due to the escape of hydrogen from the steel matrix during the cooling process,which leads to the reduction in the interfacial heat transfer and the increase in the grain size.

关键词： Strip casting Hydrogen content Interfacial heat transfer behavior contact behavior Microstructure evolution

Investigation of contact behavior on a model of the dual-mobility artificial hip joint for Asians in different inner liner thicknesses

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World Journal of Orthopedics 2024年第4期15卷 321-336页

作者： Taufiq Hidayat Muhammad Imam Ammarullah Rifky Ismail Eko Saputra M Danny Pratama Lamura Chethan K N Athanasius Priharyoto Bayuseno J Jamari Department of Mechanical Engineering Universitas Muria KudusKudus 59352Central JavaIndonesia Department of Mechanical Engineering Universitas DiponegoroSemarang 50275Central JavaIndonesia Undip Biomechanics Engineering&Research Centre Universitas DiponegoroSemarang 50275Central JavaIndonesia Center for Biomechanics Biomaterials Biomechatronics and Biosignal Processing Universitas DiponegoroSemarang 50275Central JavaIndonesia Department of Mechanical Engineering Politeknik Negeri SemarangSemarang 50275Central JavaIndonesia Department of Aeronautical and Automobile Engineering Manipal Institute of TechnologyManipalManipal Academy of Higher EducationManipal 576104KarnatakaIndia

BACKGROUND The four components that make up the current dual-mobility artificial hip joint design are the femoral head,the inner liner,the outer liner as a metal cover to prevent wear,and the acetabular cup.The acetabular cup and the outer liner were constructed of 316L stainless steel.At the same time,the inner liner was made of ultra-high-molecular-weight polyethylene(UHMWPE).As this new dual-mobility artificial hip joint has not been researched extensively,more tribological research is needed to predict wear.The thickness of the inner liner is a significant component to consider when calculating the contact pressure.AIM To make use of finite element analysis to gain a better understanding of the contact behavior in various inner liner thicknesses on a new model of a dual-mobility artificial hip joint,with the ultimate objective of determining the inner liner thickness that was most suitable for this particular type of dual-mobility artificial hip joint.METHODS In this study,the size of the femoral head was compared between two diameters(28 mm and 36 mm)and eight inner liner thicknesses ranging from 5 mm to 12 mm.Using the finite element method,the contact parameters,including the maximum contact pressure and contact area,have been evaluated in light of the Hertzian contact theory.The simulation was performed statically with dissipated energy and asymmetric behavior.The types of interaction were surface-to-surface contact and normal contact behavior.RESULTS The maximum contact pressures in the inner liner(UHMWPE)at a head diameter of 28 mm and 36 mm are between 3.7-13.5 MPa and 2.7-10.4 MPa,respectively.The maximum von Mises of the inner liner,outer liner,and acetabular cup are 2.4–11.4 MPa,15.7–44.3 MPa,and 3.7–12.6 MPa,respectively,for 28 mm head.Then the maximum von Mises stresses of the 36 mm head are 1.9-8.9 MPa for the inner liner,9.9-32.8 MPa for the outer liner,and 2.6-9.9 MPa for the acetabular cup.A head with a diameter of 28 mm should have an inner liner with a thickness of 12 mm.Whereas the head dia

关键词： contact behavior contact pressure Finite element analysis Dual-mobility Artificial hip joint

contact behavior of Worn Bearings with Elastoplastic Functionally Graded Coating Based on Mixed Elastohydrodynamic Lubrication

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Acta Mechanica Solida Sinica 2021年第1期34卷 124-136页

作者： Xue-Qian Fang Yao Ning Shao-Pu Yang Hai-Hua Wang State Key Laboratory of Mechanical behavior and System Safety of Traffic Engineering Structures Shijiazhuang Tiedao UniversityShijiazhuang050043China Department of Engineering Mechanics Shijiazhuang Tiedao UniversityShijiazhuang050043China Hebei Key Laboratory for Mechanics of Smart Materials and Structures Shijiazhuang050043China School of Mechanical Engineering Shijiazhuang Tiedao UniversityShijiazhuang050043China

The dynamic contact behavior of worn bearings with elastoplastic functionally graded coating is studied,and the interacting effect between worn band and functionally graded surface is analyzed.The surface deformation and roughness are included in the film thickness.The mixed elastohydrodynamic lubrication combined with point contact model is introduced to analyze the oil pressure in the contact zone.By using the Fourier transform method and Papkovich-Neuber potential function,the displacements and stress fields in the elastoplastic functionally graded coating are obtained.The second-order central difference method is used to solve the Reynolds equation.It is found that the repeated surface interaction can result in the sharp increase in pressure in bearings,and the oil pressure increases with increasing graded index.The entrainment of oil in the inlet and outlet zones becomes more evident if a large graded index is selected.

关键词： Wear bearings contact behavior Elastoplastic functionally graded surface Mixed elastohydrodynamic lubrication.Central difference method

Static Radical Stiffness and contact behavior of Nonpneumatic Mechanical Elastic Wheel

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Transactions of Nanjing University of Aeronautics and Astronautics 2019年第4期36卷 663-674页

作者： ZANG Liguo ZHAO Youqun SUN Haiyan LIN Fen School of Automotive and Rail Transit Nanjing Institute of TechnologyNanjing 211167P.R.China College of Energy and Power Engineering Nanjing University of Aeronautics and AstronauticsNanjing 210016P.R.China

Conventional pneumatic tires exhibit disadvantages such as puncture,blowout at high speed,pressure maintenance,etc.Owing to these structural inevitable weaknesses,non?pneumatic tires have been developed and are investigated.A non?pneumatic mechanical elastic wheel(NPMEW)is introduced and investigated as a function of static radical stiffness characteristics and contact behavior.A bench test method is utilized to improve the riding comfort and the traction traffic ability of NPMEW based on tire characteristics test rig,and the static radical stiffness characteristics and the contact behavior of NPMEW are compared with that of an insert supporting run?flat tire(ISRFT).The vertical force?deformation curves and deformed shapes and contact areas of the NPMEW and ISRFT are obtained using a set of vertical loads.The contact behavior is evaluated using extracted geometrical and mechanical feature parameters of the two tires.The results indicate that the NPMEW appears to exhibit considerably high radical stiffness,and the numerical value is dependent on the mechanical characteristic of the flexible tire body and hinge units.NPMEW demonstrates more uniform contact pressure than ISRFT within a certain loading range,and it can efficiently mitigate the problem of stress concentration in ISRFT shoulder under heavy load and enhance the wear resistance and ground grip performances.

关键词： vehicles non⁃pneumatic mechanical elastic wheel run⁃flat tire radical stiffness contact behavior

Mechanic model of water-based boundary lubricated contact based on surface force effects

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Friction 2023年第1期11卷 93-108页

作者： Yanfei FANG Liran MA College of Mechanical Engineering and Automation Huaqiao UniversityXiamen 361021China State Key Laboratory of Tribology Tsinghua University Beijing 100084China

In water-based boundary lubrication regime,the contact gaps(or boundary lubricated film thickness)and surface pressure distribution must be determined to really understand the boundary lubricated contact mechanism.However,the accurate determination of these parameters is limited.In this study,a mechanical model based on boundary lubricated contact involving surface force effects is developed.The surface force distribution characteristics,normal force vs.central film thickness curve,and macroscale water-based boundary lubricated contact are investigated numerically.The results show that hydration directly affects surface force interaction.The accurate boundary lubricated film thickness and surface pressure distribution can be obtained using this model in point contact.Furthermore,the mechanism of macroscale water-based liquid boundary lubricated contact is investigated,in which a water-based boundary lubricated film is formed under appropriate operating conditions based on surface force effects during running-in.This study can reveal the water-base boundary lubricated contact behavior and the carrying capacity of the surface force effect,and provides important design guidance for the surface force effect to achieve liquid superlubricity in water-based boundary lubricated contacts.

关键词： boundary lubricated contact surface force contact behavior roughness surface numerical model