• Title/Summary/Keyword: steel wheel

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A study on the internal high-speed grinding (고속 내면 연소에 관한 연구)

  • An, Sang-Ook;Inasaki, Ichiro
    • Journal of the Korean Society for Precision Engineering
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    • v.10 no.2
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    • pp.190-196
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    • 1993
  • Internal high speed grinding under several high grinding wheel speed condition has been performed in this study for the effects have analyzed and compared with the grinding power, grinding tangential force and accuracy of surface with the carbon tool steel(SK3). The following results have been obtained: (1) Under the workpiece speed constant condition, increasing the grinding speed, the tangential force is decreased, and on the contrary, accuracy of surface is improved. (2) Under the speed ratio (V$_{w}$/V$_{s}$) contant condition it is possible to increase the high machining efficiency constraint to tangential grinding force constant.ant.

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Behavior of Continuously Reinforced Concrete Pavement under Moving Vehicle Loads and Effecct of Steel Ratio (이동차량하중에 대한 연속철근콘크리트포장의 거동 및 철근비의 영향)

  • Kim Seong-Min;Cho Byoung-Hooi;Kwon Soon-Min
    • International Journal of Highway Engineering
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    • v.8 no.1 s.27
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    • pp.119-130
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    • 2006
  • The behavior of continuously reinforced concrete pavement (CRCP) and the effect of the steel ratio on the behavior under moving wheel loads were investigated in this study. The CRCP sections having different steel ratios of 0.6, 0.7, and 0.8% were considered to evaluate the load transfer efficiency (LTE) at transverse cracks and to investigate the strains in CRCP when the system is subjected to moving vehicle loads. The LTEs were obtained by conducting the falling weight deflectometer (FWD) tests and the tests were performed at three different times of a day to find the curling effect due to the daily temperature changes in CRCP. The strains in the concrete slab and the bond braker layer of the CRCP system under moving vehicle loads were obtained using the embedded strain gages. The results of this study show that the LTEs at transverse cracks are very high and not affected by the time of testing and the steel ratio. The strains in CRCP under vehicle loads become smaller as the vehicle speed increases or as the wandering distance increases; however, the strains are not clearly affected by the steel ratio.

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Fabrication Characteristics of Slag Fiber by 4 Wheel System (4휠 시스템을 이용한 슬래그 섬유의 제조)

  • Song, Yeong-Hwan;Seong, Hwan-Goo;Park, Soo-Han;Wang, Xiaosong;Hur, Bo-Young
    • Journal of Korea Foundry Society
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    • v.26 no.5
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    • pp.222-226
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    • 2006
  • Steel making slag has gained a considerable attraction as one candidate of eco-materials in research fields for recycling resources. Thus, many researches have been performed but were limited to development of substitute for cement being used in the construction field. A little research work also has been done on development of higher value-added materials, including heat resistant and sound absorbing materials. For this reason, the present study were focused on macrostructure characterization of fabricated slag fibers which are applicable to heat resistant materials. The slag fibers were fabricated through a modified melt extraction method. The processing variables employed were the wheel speed and molten slag temperature. The synthesized fibers were characterized by optical microscope and scanning electron microscopy. It was found that the wheel speed of 1400 rpm generated better quality of mineral fibers in terms of the relative amount of shot, diameter and length. This was attributed to the relative extent of contact width between the flowing melt and the rotating wheel. The thickness of the slag fibers also were decreased with increasing the slag melt temperature due mainly to significant decrease in the viscosity of the slag melt. In addition, the lower melt temperature caused an increase in number of shots plus the mineral fibers.

A Preliminary Study of Roller Types for Chip Seals Construction (Chip Seals 시공을 위한 롤러 종류에 따른 기초적인 연구)

  • Lee, Jae-Jun;Kim, R. Young-Soo
    • International Journal of Highway Engineering
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    • v.12 no.3
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    • pp.79-85
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    • 2010
  • This paper presents a preliminary study of roller types for chip seals based on aggregate retention performance. Chip seal test sections composed of single seals of granite 78M aggregate and CRS-2 emulsion were constructed using three different roller types: the pneumatic tire roller, steel wheel roller, and combination roller. In order to investigate the performance of these rollers effectively, it is critical to test chip seal samples obtained directly from field construction. Therefore, test sections were constructed on New Sandy Hill Church Road near Bailey, North Carolina. Chip seal samples obtained from these sections were used for laboratory testing. The aggregate retention performance was evaluated using the flip-over test (FOT), Vialit test, and the third-scale Model Mobile Loading Simulator (MMLS3). Based on the test results and visual observation, both the pneumatic roller and the combination roller used together are recommended to improve chip seal performance with the sequence of the pneumatic roller rolling first followed by the combination roller.

Fatigue evaluation and CFRP strengthening of diaphragm cutouts in orthotropic steel decks

  • Ke, Lu;Li, Chuanxi;He, Jun;Lu, Yongjun;Jiao, Yang;Liu, Yongming
    • Steel and Composite Structures
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    • v.39 no.4
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    • pp.453-469
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    • 2021
  • The cracking at the transverse diaphragm cutout is one of the most severe fatigue failures threatening orthotropic steel decks (OSDs), whose mechanisms and crack treatment techniques have not been fully studied. In this paper, full-scale experiments were first performed to investigate the fatigue performance of polished cutouts involving the effect of an artificial geometrical defect. Following this, comparative experimental testing for defective cutouts strengthened with carbon fiber-reinforced polymer (CFRP) was carried out. Numerical finite element analysis was also performed to verify and explain the experimental observations. Results show that the combinative effect of the wheel load and thermal residual stress constitutes the external driving force for the fatigue cracking of the cutout. Initial geometrical defects are confirmed as a critical factor affecting the fatigue cracking. The principal stress 6 mm away from the free edge of the cutout can be adopted as the nominal stress of the cutout during fatigue evaluation, and the fatigue resistance of polished cutouts is higher than Grade A in AASHTO specification. The bonded CFRP system is highly effective in extending the fatigue life of the defective cutouts. The present study provides some new insights into the fatigue evaluation and repair of OSDs.

Proposal of the Track Layout Criterion for the Light Rail Transit (경량전철 선로선형기준에 대한 제안)

  • 오지택;한승용;윤태양;성택룡
    • Proceedings of the KSR Conference
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    • 2000.11a
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    • pp.111-118
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    • 2000
  • This paper proposes the track layout criterion for the LRT(light rail transit). All criterions established concerning dimension and performance of LRT vehicles that are three types. Types of vehices are AGT(automated guided train) steel wheel. AGT rubber tire and LIM(linear induction motor). Using theoritical approach, adaptation and validity of criterions are verified. Proposed criterions may provide a standard scheme for design and construction of the infrastructure on LRT.

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A Model Design on the Korean AGT System (한국형 경량 전철 모델 연구)

  • 최출헌;한석윤;신학수
    • Proceedings of the KSR Conference
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    • 2001.05a
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    • pp.114-122
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    • 2001
  • As of these, the exterior design of the public transportation systems, especially electric multiple, tends to mimic advanced country's design rather than design of car shape reflecting cultural and spiritual background. However, in the new transportation system, the design which satisfies the transportation demand must be changed into the design which creates transportation demand. In this respect, this research focuses on the factor's embodiment which is perceived by Korean passenger sympathetic to cultural and spiritual needs. The results of this research are Korean AGT design on rubber tire AGT, steel wheel AGT, LM AGT system and environmental design related to AGT systems.

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Local Deformation Analysis of the Orthotropic Steel Bridge Deck Due to Wheel Loadings Using FSM and FEM (윤하중에 의한 강바닥판 교면포장의 종방향균열 관련 수치해석법 개발)

  • Jeong, Jin Seok;Jung, Myung Rag;Ock, Chang Kwon;Lee, Won Tae;Kim, Moon Young
    • Journal of Korean Society of Steel Construction
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    • v.28 no.4
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    • pp.243-251
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    • 2016
  • Longitudinally structural cracks are sometimes observed in the pavement on steel plate deck bridges because traffic truck loadings can cause large local deformations of the thin deck plate stiffened by longitudinal and transverse beams. In this study, an improved finite strip method using flat-shell strip, prism, and link elements is presented to investigate local deformations of steel decks with pavements in which flexural and torsional stiffness effects of thin floor beams are rigorously taken into account. A simplified deck model extracted from steel plate-girder bridges is analyzed using the developed FSM and the commercial FE program, ABAQUS and also, their numerical results are compared and discussed.

Load Distribution Factors for Determinating Shear Force in Steel Box Girder Bridges (강상자형교의 전단력 산정을 위한 하중분배계수)

  • Song, Jea Ho;Kim, Min Wook;Kim, Il Su;Oh, Jin Woo
    • Journal of the Korea institute for structural maintenance and inspection
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    • v.15 no.2
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    • pp.88-97
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    • 2011
  • For Korean design provisions are not equipped for skewed steel box girder bridges, when American provisions are adopted, load distribution factors different from real behavior are determinated. Furthermore the possibility of over or under estimated bridge design involves. The aim of this study is to provide more rational load distribution factor formulas based on real behavior for shear at obtuse corner of skewed steel box girder bridges. In order to accomplish the aim finite element analysis for a variety of skewed steel box girder bridge structural models is carried out, and each parameters degree of influence on wheel load distribution factors of skewed steel box girder bridges are analyzed. Then multiple regression analysis is fulfilled in order to propose formulas for determinating shear force load distribution factor of skewed steel box girder bridges.

Rolling Contact Fatigue Behavior and Microstructure Control to Medium Carbon Steel Base Hot Forgings (중탄소계 열간단조품의 미세조직과 구름피로거동)

  • Lee J. S.;Son C. H.;Moon H. K.;Song B. H.;Park C. N.
    • Proceedings of the Korean Society for Technology of Plasticity Conference
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    • 2005.05a
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    • pp.287-290
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    • 2005
  • Once hot forgings for automotive parts such as wheel bearing flange to which cyclic asymmetric bending stress is continuously applied are produced, it is necessary to control their microstructure to obtain superior mechanical properties. It is however hard to control the microstructure uniformly because the strength is reduced as coarsening of ferrite grains. To investigate the microstructural alteration according to process variables during hot working, the variation of the ferrite grain size was studied by utilizing of the computer aided servo-hydraulic Gleeble tester which is hot deformation behavior reproduction equipment. In addition, the effect of the ferrite grain size of raw material on the austenite grain behavior of hot forgings was also examined. The rolling contact fatigue resistance of the induction hardened SAE 1055 steel was compared with the occasion of the same condition of SAE52100 bearing steel. As a result, it was confirmed that the ferrite grain sizes of the forgings depend on the heating temperature and cooling start temperature during hot forging and cooling processes. The induction hardened SAE1055 steel showed a superior rolling contact fatigue resistance to the induction hardened SAE52100 steel. The reason is that SAE1055 steel is freer from the material defect such as segregation than the comparative steel.

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