• Title/Summary/Keyword: radial direction

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Calculation of equivalent friction coefficients in V-belt (V벨트에서 상당마찰계수 계산)

  • Hong, J.P.
    • Proceedings of the KSME Conference
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    • 2001.11a
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    • pp.740-745
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    • 2001
  • There are two kinds of method to calculate the equivalent friction coefficients at V groove. One is to consider the firction in radial direction. The other is to neglect the friection in radial direction. The values calculated from the two methods is different of which ratio is in the range from two times to five times. So it is necessary to study which is correct in the view of force equilibrium and machine design.

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Comparison and Analysis on magnetic structures of Switched Reluctance Motors (Switched Reluctance Motor의 자기적 구조에 대한 비교 해석)

  • Oh, Seok-Gyu
    • Journal of the Korea Institute of Information and Communication Engineering
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    • v.20 no.1
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    • pp.131-141
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    • 2016
  • SRM is designed to meet operating standards such as low cost, simple magnetic structure, a desired operating speed range, high efficiency, high performance, and good matching for DC power. The magnetic flux of SRM is independent of its direction to develop a torque and it allows the flexible characteristics of the magnetic structure for SRM. In this paper, SRM can widely classify two types, Radial-Flux SRM and Axial-Flux SRM, according to the flux direction. Radial-Flux SRM includes Conventional, Segmented stator and rotor, and Double stator SRM, etc. and Axial-Flux SRM includes C-core stator and the Axial-airgap SRM. This paper is subjected the basic characteristics to select the best of the magnetic structure of SRM in the appropriate application by the classification of SRM.

A Study on the Forming Characteristics of Radial Extrusions (레이디얼압출의 성형특성에 관한 연구)

  • 이수형;황병복
    • Transactions of Materials Processing
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    • v.8 no.6
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    • pp.604-611
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    • 1999
  • This paper is concerned with the family of parts that generally feature a central hub with radial protrusions. As opposed to conventional forward and backward extrusion, in which the material flows in a direction parallel to that of the punch or die motion, the material flows perpendicular to the punch motion in radial extrusion. Three variants of radial extrusion of a collar or flange are investigated. Case I involves forcing a cylindrical billet against a flat die, Case II involves deformation against a stationary punch recessed in the lower die, and Case III involves both the upper and lower punches moving together toward the center of the billet. Extensive simulational work is performed with each case to see the process conditions in terms of forging load, balanced and symmetrical flow in the flange. Also, the effect of the gap size and die corner radii to the material flow are investigated. In this study, the forming characteristics of radial extrusion will be considered by comparing the forces, shapes etc. The design factors during radial extrusion are investigated by the rigid-plastic FEM simulation.

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Stress analysis of marine diesel engine piston (선박용 디젤기관의 피스톤 응력해석)

  • 한문식;김상철
    • Journal of Advanced Marine Engineering and Technology
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    • v.9 no.2
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    • pp.143-152
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    • 1985
  • In this paper, temperature distribution and thermal stress are investigated considering engine peak pressure and the time average temperature distribution in the piston under running conditions for the marine diesel engine. The induced stress are calculated by the Finite Element Method (FEM). The results obtained are summerized as follows. 1) The results calculated by the FEM present good agreement with other numerical solution in literatures. 2) It is comfirmed that the maximum compressive stresses are induced in the part of outside wall between the piston crown and the pin bush 3) In the axial direction, the hoop stresses are changed its sign at the portion of crown near the inner wall side. 4) Large gradient of temperature is shown in the piston crown near the side wall in the axial direction, in the part between the piston crown and the pin bush in radial direction. 5) In case of stress distribution of piston wall surface in the axial direction, the hoop stress is a little greater than axial stress, and the latter is greater than the radial stress.

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Dynamic Viscoelasticity of Hot Pressed Wood (열압재목재(熱壓縡木材)의 동적점탄성(動的粘彈性))

  • Hong, Byung-Wha
    • Journal of the Korean Wood Science and Technology
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    • v.12 no.4
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    • pp.3-10
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    • 1984
  • In hot pressed wood of Pseudotsuga menziesii compressed to 0 - 50 percent at temperature 60 - $180^{\circ}C$, relative humidity conditions affecting dynamic Young's modulus of elasticity and internal friction were investigated. The results obtained are summarized as follows: Moisture absorption of the hot pressed wood decreased with increasing press temperature, but there was no effect on the amount of compression. Thickness swelling dereased with increasing press temperature, and increased with increasing amount of compression. In general, dynamic Young's modulus of elasticity showed a straight line with increasing specific gravity of specimens. Dynamic Young's modulus of elasticity decreased with increasing moisture content, but internal friction increased with increasing amount of moisture content. Dynamic Young's modulus of R specimens pressed in the radial direction showed hight values than T specimens pressed in the tangential direction.

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Effect of Mold Dimensions on Temperature Distribution of Die during Plasma Activated Sintering (플라즈마 활성 소결에 있어서 다이스의 온도분포에 미치는 몰드 크기의 영향)

  • Lee Gil-Geun;Park IK-Min
    • Journal of Powder Materials
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    • v.11 no.5
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    • pp.363-368
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    • 2004
  • In the present study, the focus is on the analysis of the effect of the mold dimensions on the temperature distribution of a die during plasma activated sintering. The temperature distribution of a cylindrical mold with various dimensions was measured using K-type thermocouples. The temperature homogeneity of the die was studied based on the direction and dimensions of the die. A temperature gradient existed in the radial direction of the die during the plasma activated sintering. Also, the magnitude of the temperature gradient was increased with increasing sintering temperature. In the longitudinal direction, however, there was no temperature gradient. The temperature gradient of the die in the radial direction strongly depended on a ratio of die volume to punch area.

Design of a Novel 3D Printed Harmonic Drive and Analysis of its Application (3D 프린팅 기법을 이용한 하모닉 드라이브(Harmonic Drive) 설계 및 응용 분석)

  • Kim, Sang-Hyun;Byeon, Chang-Sup;Lee, Chul-Hee
    • Tribology and Lubricants
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    • v.38 no.1
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    • pp.27-31
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    • 2022
  • Harmonic drives have attracted increasing attention with the development of materials, parts, and related equipment. Harmonic drives exhibit high deceleration, high accuracy, and light weight. The stiffness of flexible splines according to the radial load is studied using a commercial FEM program to design the structure of the flexible spline and finite element to improve the weight and price competitiveness of harmonic drives. In addition, several studies have measured and compared friction coefficients based on 3D printed tread patterns. However, owing to the characteristics of plastic materials, a decrease in stiffness in the radial direction is inevitable. To prevent a decrease in stiffness in the radial direction, we designed and manufactured flex splines with a wrinkle shape. Through structural analysis, the reaction force and stiffness in the radial direction were determined. In addition, the maximum angle of the mound was derived by theoretical calculations, and the performance of the harmonic drive was compared with the results obtained in the mound experiment. Structural analysis shows that the shape of wrinkles decreased the stress and reaction force and increased the safety factor in comparison with that of the circular shape. During performance verification through continuous experiments, the developed harmonic drive showed continuous performance similar to that of an actual tank model. It is expected that the flex spline with a compliant spring and wrinkle shape will prevent a decrease in the radial stiffness.

Flow Behavior of Safranine Solution in Prunus sargentii Rehder

  • Hong, Seong-Du;Ahmed, Sheikh Ali;Chun, Su-Kyoung
    • Journal of the Korea Furniture Society
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    • v.18 no.4
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    • pp.282-286
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    • 2007
  • An experiment was conducted to compare the 1% safranine solution flow depth in radial and longitudinal direction of Prunus sargentii. Longitudinal flow of safranine solution was found higher than radial flow. Body ray parenchyma was found more permeable than marginal ray parenchyma and it was about 1.3 times higher. Intercellular space conducted safranine solution more than ray parenchyma. Vessel was found to be the main avenue for liquid conduction in longitudinal direction. Different anatomical features of ray, vessel and fiber affected the penetration depth of safranine solution. Moreover initial penetration depth was found to be high and thereafter decreased gradually.

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Essential Oil Penetration Depth in Prunus sargentii Rehder

  • Ahmed, Sheikh Ali;Hong, Seong-Du;Chun, Su-Kyoung
    • Journal of the Korea Furniture Society
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    • v.18 no.4
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    • pp.307-311
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    • 2007
  • An experiment was conducted to know the essential oil penetration depth in radial and longitudinal direction of Prunus sargentii. Oil penetration depth was found greater than radial flow depth. Vessel conducted oil more than wood fiber. In radial direction, body ray parenchyma was found more permeable than marginal ray parenchyma and it was about 138% times higher. Furthermore penetration depth of oil in intercellular space was greater than ray parenchyma and it was about 250% higher than ray parenchymas. Initial flow speed was found high and then it gradually decreased.

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A TMR Budget Design for 100kTPI Hard Disk Drives Using a Head Gimbal Assembly with Radial Motion Capability (100kTPI급 하드 디스크 드라이브 TMR 설계를 위한 SUSPENSION에 관한 연구)

  • Oh, Dong-Ho;Kang, Seong-Woo;Han, Yun-Sik;Kim, Young-Hoon;Koh, Jeong-Seok;Hwang, Tae-Yeon
    • Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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    • 2002.11b
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    • pp.140-145
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    • 2002
  • In high-capacity disk drives with ever-growing track density, the allowable level of position error signal (PES) is becoming smaller and smaller. A substantial portion of the PES is caused by disk vibration. This can be reduced by using a head gimbal assemblies (HGAs) that do not confine the slider movement to the vertical direction to disks, but allow movement to the radial direction of disks with respect to disk vibration. Several types of HGAs are proposed for such radial motion of the slider. Experimental results show that the PES levels are reduced by the proposed HGA-design concepts.

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