• Title/Summary/Keyword: Friction Joint

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Friction and Lubrication Behaviors of Rabbit Joint Cartilage (토끼 관절연골의 마찰 및 윤활 특성)

  • 이권용;이홍철
    • Proceedings of the Korean Society of Tribologists and Lubrication Engineers Conference
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    • 2000.06a
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    • pp.42-47
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    • 2000
  • The friction and lubrication characteristics of joint cartilage were investigated using the metatarso-phalangeal joint cartilage of rabbit against rotating stainless steel disk. Friction tests were conducted by dry and bovine serum lubricated sliding at room and body temperatures. For the dry sliding tests, low friction coefficient of 0.1-0.15 was observed at the early period of test, and then the friction coefficient increased as a test continued. With increasing applied load the early period of low friction lengthens. For the lubricated sliding tests, the coefficient of friction decreased as the applied load increased. And also the coefficient of friction decreased continuously to 0.07 as the test duration increases. These results can be interpreted that the squeeze or weeping lubrication mechanism dominates the friction and lubrication characteristics in the joint cartilage of rabbit.

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Friction and Lubrication Behaviors of Rabbit Joint Cartilage (토끼 관절연골의 마찰 및 윤활 특성)

  • 이권용;이홍철
    • Tribology and Lubricants
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    • v.17 no.4
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    • pp.307-311
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    • 2001
  • The friction and lubrication characteristics of joint cartilage were investigated using the metatarso-phalangeal joint cartilage of rabbit against rotating stainless steel disk. Friction tests were conducted by dry and bovine serum lubricated sliding at room and body temperatures. For the dry sliding tests, low friction coefficient of 0.1-0.15 was observed at the early period of test, and then the friction coefficient increased as a test continued. With increasing applied load the early period of low friction lengthens. For the lubricated sliding tests, the coefficient of friction decreased as the applied load increased. And also the coefficient of friction decreased continuously to 0.07 as the test duration increases. These results can be interpreted that the squeeze or weeping lubrication mechanism dominates the friction and lubrication characteristics in the joint cartilage of rabbit.

MEASUREMENT AND CHARACTERIZATION OF FRICTION IN AUTOMOTIVE DRIVESHAFT JOINTS

  • Lee, C.H.
    • International Journal of Automotive Technology
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    • v.8 no.6
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    • pp.723-730
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    • 2007
  • The typical design of automotive driveshafts generally utilizes Constant Velocity(CV) joints as a solution to NVH. CV joints are an integral part of vehicles and significantly affect steering, suspension, and vehicle vibration comfort levels. Thus, CV joints have been favored over universal joints due to the constant velocity torque transfer and plunging capability. Although CV joints are common in vehicle applications, current research works on modeling CV joint friction and assumes constant empirical friction coefficient values. However, such models are long known to be inaccurate, especially under dynamic conditions, which is the case for CV joints. In this paper, an instrumented advanced CV joint friction apparatus was developed to measure the internal friction behavior of CV joints using actual tripod-type joint assemblies. The setup is capable of measuring key performance of friction under different realistic operating conditions of oscillatory speeds, torque and joint installation angles. The apparatus incorporates a custom-installed triaxial force sensor inside of the joint to measure the internal CV joint forces(including friction). Using the designed test setup, the intrinsic interfacial parameters of CV joints were investigated in order to understand their contact and friction mechanisms. The results provide a better understanding of CV joint friction characteristics in developing improved automotive driveshafts.

Development of Internal Friction Model in Automotive Constant Velocity Joints (자동차용 등속 조인트의 내부 마찰 모델 개발)

  • Lee, Chul-Hee;Jang, Min-Gyu
    • Tribology and Lubricants
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    • v.24 no.5
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    • pp.215-220
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    • 2008
  • An internal friction model was developed to model the frictional behavior of automotive Constant Velocity (CV) joints by using the test data from an instrumented CV joint friction apparatus with actual driveshaft assemblies. Experiments were conduced under different realistic operating conditions of oscillatory speeds, CV joint articulation angles, lubrication, and torque. The experimental data were used to develop a physics-based semi-empirical CV joint internal friction coefficient model as a function of different CV Joint operating parameters. It was found that the proposed friction model captures the experimental results well not only the static behavior of friction coefficient, but also the dynamic friction terms, which is the main source of force that causes vehicle vibration problems.

Friction and wear properties of carbon fiber reinforced epoxy composite for the artificial hip joint application (인공고관절 모사조건하에서의 탄소섬유 복합재료의 마찰 및 마모 특성)

  • 송영석;윤재륜
    • Proceedings of the Korean Society For Composite Materials Conference
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    • 1999.11a
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    • pp.239-241
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    • 1999
  • Recently, the friction and wear behaviors of UHMWPE, ceramic and metal is being researched actively for the use as an artificial hip-joint. In this study, because of good wear properties of carbon fiber, we made experiments about the friction and wear of carbon fiber reinforced epoxy composite under the lubricative and the dry condition. The possibilities of carbon-carbon composite for the artificial hip joint application was studied from this results.

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EVALUATION OF FRICTION WELDABILITY OF TYPE 5052 ALALLOY/LOW CARBON STEEL JOINT.

  • Kim, Kyung-Kyun;Lee, Won-Bae;Yeon, Yun-Mo;Kim, Dae-Up;Jung, Seung-Boo
    • Proceedings of the KWS Conference
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    • 2002.10a
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    • pp.528-533
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    • 2002
  • The mechanical and metallurgical properties of friction welded joints type 5052 Al alloy/A36 steel have been studied in this paper. The joint strength increased with increasing upset pressure and friction time till it reached the critical value. The joint strength was fixed at low strength compare to that of base metal in the case of increasing friction time. Microstructure of 5052 Al alloy was greatly deformed near the weld interface. The very fine and equaxied grain structure was observed at the near interface. The elongated grain was formed outside dynamic recrystallizatoin region at the peripheral part, while the A36 steel' side was not deformed. The hardness of the near interface was slightly softer than that of 5052 Al alloy base metal. The maximum softening width was about 8mm from the interface. In the present work, the friction welding condition, t$_1$=0.5sec, P$_2$=137.5MPa, showed a maximum joint strength (202MPa) when friction pressure, upset time and rotation speed were fixed at 75MPa, 5sec, 2000rev/min and these were the optimum friction welding condition of 5052Al/A36 steel joints.

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Friction Stir Welding Tool Geometries Affecting Tensile Strength of AA6063-T1 Aluminum Alloy Butt Joint

  • Kimapong, Kittipong;Kaewwichit, Jesada;Roybang, Waraporn;Poonnayom, Pramote;Chantasri, Sakchai
    • International journal of advanced smart convergence
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    • v.4 no.1
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    • pp.145-153
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    • 2015
  • Friction Stir Welding (FSW) is a solid state welding that could successfully weld the difficult-to-weldmaterials such as an aluminum alloy. In this welding process, the stirrer of the welding tool is one of the important factors for producing the perfect sound joint that indicates the higher joint strength. So, this report aims to apply the friction stir welding using various stirrer geometries to weld the AA6063-T1 aluminum alloy butt joint, investigates the mechanical properties of the joint and then compares the mechanical properties with the microstructure of the joint. An experiment was started by applying the friction stir welding process to weld a 6.3 mm thickness of AA6063-T1 aluminum alloy butt joint. A study of the stirrer geometries effect such as a cylindrical geometry, a cone geometry, a left screw geometry and a right screw geometry at a rotational speed of 2000 rpm and a welding speed of 50-200 mm/min was performed. The mechanical properties such as a tensile strength and a hardness of the joint were also investigated and compared with the microstructure of the joint. The results are as follows. A variation of FSW Stirrer shape directly affected the quality AA6063-T1 aluminum alloy butt joint. A cylindrical stirrer shape and a cone stirrer shape produced the void defect at the bottom part of the weld metal and initiated the failure of the joint when the joint was subjected to the load during the tensile test. Left and right screw stirrer shapes gave the sound joint with no void defect in the weld metal and affected to increase the joint strength that was higher than that of the aluminum base metal.

Effect of Contact Pressure on the Variations in Coefficients of Friction Between Porcine Knee Joint Cartilage and Co-Cr Alloy in a Repeat Pass Sliding Motion (반복 회전운동에서 코발트 크롬 합금과 미끄럼 접촉하는 돼지 무릎 관절연골의 접촉압력이 마찰계수 변화에 미치는 영향)

  • Lee, Kwon-Yong;Kim, Hwan;Lee, Young-Ze
    • Tribology and Lubricants
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    • v.25 no.4
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    • pp.231-235
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    • 2009
  • In this study, the influence of contact pressure on the variation in coefficients of friction between porcine knee joint cartilage and Co-Cr alloy in a repeat pass sliding motion was investigated. Flat-ended cartilage pin specimens(9 mm diameter, 8 mm long) were prepared from porcine(6 months old) knee joints by a drill-type punch. Friction tests were conducted by using a pin-on-disk type friction tester for an hour in PBS lubricated condition under the contact pressures of 0.5, 1 and 2 MPa with 50 mm distance per a cycle at ambient condition. As a result, coefficients of friction increased as the test duration increased for all contact pressures. The maximum coefficients of friction were 0.082, 0.06 and 0.098 for 0.5, 1, and 2 MPa, respectively. It showed that coefficients of friction of porcine knee joint cartilage against Co-Cr alloy depended on the level of contact pressure and related to squeeze film lubrication mechanism.

Research on Friction Characteristics of Constant Velocity Joint Grease (등속조인트용 그리스 마찰특성 연구)

  • Lee, Sung Uk;Bae, Dae Yoon
    • Tribology and Lubricants
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    • v.29 no.4
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    • pp.223-227
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    • 2013
  • A GAF (generated axial force) is produced at a plunging-type CVJ (constant velocity joint). A high GAF can cause vibrations in a vehicle. Grease is used to reduce friction between the roller and the track of the outer case of a CVJ. The grease performance depends on the surface conditions and operating temperature. The surface of the outer case is extremely rough and hard. In recent times, the maximum operating temperature of CVJs has crossed $140^{\circ}C$, because the exhaust line is now located close to the CVJ. In this study, we examined the friction characteristics of friction additives at $25-150^{\circ}C$ and determined an optimal formulation with a low friction coefficient. This formulation can be used to develop low-friction grease that can reduce the GAF produced at a CVJ by approximately 7-26%.

A study on the mechanical properties of copper-titanium friction-welded joint (마찰압접에 의한 Cu와 Ti 압접부의 기계적 특성에 관한 연구)

  • 김성연;연윤모;김대업;정승부;서창제
    • Proceedings of the KWS Conference
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    • 2000.10a
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    • pp.192-195
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    • 2000
  • This paper describes a fundamental investigation of the friction welding condition for pure copper/pure titanium and the effect of friction time, upset pressure on the mechanical and metallurgical properties of friction welding. Under the constant upset pressure, the tensile strength make a little difference with an increase in friction time. At the constant friction time, the tensile strength increased with an increase in upset pressure. The tensile fracture of Cu to Ti joint occurred in Cu base material near interface.

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