• Title/Summary/Keyword: interface friction

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Characteristics of Friction Angles between the Nak-dong River Sand and Construction Materials by Direct Shear Test (낙동강 모래와 건설재료간의 직접전단시험에 의한 마찰각 특성)

  • Kim, Young-Su;Kim, Dae-Man
    • Journal of the Korean Geotechnical Society
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    • v.25 no.4
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    • pp.105-112
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    • 2009
  • In this study, a series of direct shear tests were performed to investigate the characteristics of friction angles for sands and interface friction angle between sands and construction materials with respect to different relative density of the Nak-dong River sands and shearing velocity. The result of the test shows that friction angles of sands are always higher than interface friction angle between sands and construction materials. As the shearing velocity get faster, the friction angles of sand became higher. With respect to the density of sand by reducing void ratio, friction angles increase linearly, and relevant equations were proposed to calculate the friction angle by changing void ratio and relative density of sand. The interface roughness of construction materials was also an important factor in interface friction angle.

A study on the Measurement of Interface Friction between Soils and Fibers (흙과 섬유의 상호마찰 특성의 측정에 관한 연구)

  • 장병욱;서동욱;박영곤
    • Proceedings of the Korean Society of Agricultural Engineers Conference
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    • 1998.10a
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    • pp.467-472
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    • 1998
  • The interface friction angle between soil and fibers is important to evaluate improvement of the shear strength on fiber mixed soils. Direct shear test and pullout tort conducted by an apparatus made specially for the purpose of this study, was analyzed to know how fiber and soils affect on interface friction angle. By the results, The value of interface friction angle of sandy soils is larger than that of clayey soils. As a diameter of fiber is large, the value of friction coefficient of sandy soil is increase and that of clayey soil is decrease. An interface friction angle of well graded soil is larger value than that of uniform graded soil

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An Evaluation Method of Fracture Toughness on Interface Crack in Friction Welded Dissimilar Materials (이종 마찰용접재의 계면균열에 대한 파괴인성의 평가방법)

  • Chung, Nam-Yong;Park, Cheol-Hee
    • Transactions of the Korean Society of Automotive Engineers
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    • v.15 no.4
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    • pp.171-177
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    • 2007
  • In this paper, an evaluation method of fracture toughness on interface cracks was investigated in friction welded dissimilar materials with interfacial edge cracks. To establish a reasonable strength evaluation method and fracture criterion, it is necessary to analyze stress intensity factor under the load and residual stress condition on friction welded interface between dissimilar materials. The friction welded specimens with an edged crack were prepared for analysis of stress intensity by using the boundary element method (BEM) and the fracture toughness. A quantitative fracture criterion for friction welded STS 304/SM 45C with interface crack is suggested by using stress intensity factor, F and the results of fracture toughness experiment.

Design of an Haptic Tactile Interface (HTI) with Friction Coefficient Measurements

  • Winter, Christophe;Perriard, Yves
    • Journal of international Conference on Electrical Machines and Systems
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    • v.2 no.4
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    • pp.436-440
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    • 2013
  • An haptic tactile interface (HTI) is presented with its modeling. Its design is dedicated to perform friction coefficient measurement to characterize reachable feelings with that kind of interface. Friction measurements are presented and discussed.

A Study on the Mechanical Properties of the Friction Welding with Hollow and Solid Shaft of SM45C (SM45C의 중실축과 중공축의 마찰용접 특성에 관한 연구)

  • Koo, Keon-Seop;Choe, Won-Yong
    • Journal of the Korean Society of Manufacturing Technology Engineers
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    • v.19 no.6
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    • pp.841-846
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    • 2010
  • The present study examined the mechanical properties of the friction welding with hollow and solid shaft of SM45, of which the diameter is 25.2mm and 33mm. Friction welding was conducted at welding conditions of 2,000rpm, friction pressure of 50MPa, upset pressure of 70MPa, friction time of 0.4sec to 1.4sec by increasing 0.2sec, upset time of 2.0 sec including variable such as friction time are following. Under these conditions, a tensile test, a hardness test and a microstructure of weld interface were studied. The results were as follows : When the friction time was 1.0 seconds under the conditions, the maximum tensile strength of the friction weld happened to be 1,094MPa, which is 120% compared with the tensile strength of SM45C base metal. The upset length linearly increased as friction time increased. According to the hardness test, the hardness distribution of the weld interface was formed from 475Hv to 739Hv. HAZ(Heat Affected Zone) was formed from the weld interface to 2mm of SM45C.

Interface friction in the service load assessment of slab-on-girder bridge beams

  • Seracino, R.;Kerby-Eaton, S.E.;Oehlers, D.J.
    • Steel and Composite Structures
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    • v.5 no.4
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    • pp.259-269
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    • 2005
  • Many slab-on-girder bridges around the world are being assessed because they are approaching the end of their anticipated design lives or codes are permitting higher allowable loads. Current analytical techniques assume that the concrete and steel components act independently, typically requiring full-scale load testing to more accurately predict the remaining strength or endurance of the structure. However, many of the load tests carried out on these types of bridges would be unnecessary if the degree of interaction resulting from friction at the steel-concrete interface could be adequately modeled. Experimental testing confirmed that interface friction has a negligible effect on the flexural capacity of a slab-on-girder beam however, it also showed that interface friction is significant under serviceability loading. This has led to the development of an improved analytical technique which is presented in this paper and referred to as the slab-on-girder mixed analysis service load assessment approach.

Friction Welding of MA754 ODS Alloy Produced by Mechanical Alloying (기계적 합금법으로 제조된 MA754 산화물 분산강화 합금의 마찰압접에 관한 연구)

  • 강지훈
    • Journal of Powder Materials
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    • v.1 no.2
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    • pp.198-207
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    • 1994
  • In order to find an optimal friction-welding condition for Ni-base ODS alloy (MA 754) produced by mechanical alloying, joint experiments were performed with various conditions of friction pressures (50~500 MPa), friction times (1~5 sec) and upset pressures (50~600 MPa). The optimal friction pressure and upset pressure must be above 400 MPa and 500 MPa, respectively, which are determined by tensile strengths and fracture features of as-welded joints. A maximum stress설h of 975 MPa could be obtained under these pressure conditions at friction time of 2 sec. Microstructural features of bonded interface by optical microscope and SEM revealed that the interface regions of all specimens are consisted with three distinct regions and defects such as voids, cracks and wavy interfaces exist in the joints produced under not-optimized conditions. EDS results showed that these defects include oxides composed with elements of Al, Y and Ti. The hardness on the bonded interface was higher than in the base metal region. Specimens fractured in bonded interface region had lower strength values compared to those fractured in base metal region. Surfaces of the former showed a typical intergranular fracture.

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Analysis of Stress Singularities on Interfaces of Friction Welded Dissimilar Materials (마찰용접에 의한 이종재 접합계면에 대한 응력특이성의 해석)

  • Chung, Nam-Yong;Park, Chul-Hee
    • Transactions of the Korean Society of Automotive Engineers
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    • v.13 no.2
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    • pp.142-148
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    • 2005
  • In this paper, the stress singularity on interface of friction welded dissimilar materials was investigated by using 2-dimensional elastic boundary element method. It is required that stress distributions and stress singularities on an interface for friction welded dissimilar materials analize to establish strength evaluation. The stress singularity index ($\lambda$) and stress singularity factor ($\Gamma$) were calculated from the results of stress analysis. The stress singularities on variations for shapes and thickness of friction welded flashes were analized and discussed. This paper suggested that the strength evalution by using the stress singularity factors as fracture parameters, considering the stress singularity on an interface edge of friction welded dissimilar materials were very useful.

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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Characteristics of Friction Welding of Bulk Metallic Glass Rods and Tubes (벌크 비정질 금속 봉재 및 튜브재의 마찰접합 특성)

  • Shin, Hyung-Seop;Park, Jung-Soo;Jung, Yoon-Chul
    • Transactions of the Korean Society of Mechanical Engineers A
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    • v.33 no.7
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    • pp.687-692
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    • 2009
  • The friction welding of Zr-based bulk metallic glass (BMG) rods and tubes to similar BMGs, and to crystalline metals were performed. An infrared thermal imager (FLIR-Thermal Cam SC-2000) was used to measure the temperature distribution at joining interface of the specimens during friction welding. All BMGs adopted in this study showed a successful friction joining to similar BMG. The shape of the protrusion formed at the weld interface were examined. In order to characterize the friction weld interface, the micrographic observation and the X-ray diffraction analysis on the weld cross-section were carried out. The obtained results were discussed based on the temperature distribution measured at the weld interface A successful joining of the BMGs to crystalline metals could be obtained for certain pairs of the material combination through the precise control of the friction condition. The residual strength after dissimilar friction welding of BMG was evaluated by the four-point bending test and compared with the cases of friction welding to similar materials.