• Title/Summary/Keyword: Kinematically Admissible

Search Result 74, Processing Time 0.018 seconds

A Study on the Forging of Cylindrical Parts with Internal Serrations (내부에 세레이션홈이 존재하는 원통형 제품의 단조에 관한 연구)

  • Park, J.C.;Cho, H.Y.;Min, G.S.
    • Journal of the Korean Society for Precision Engineering
    • /
    • v.14 no.6
    • /
    • pp.142-148
    • /
    • 1997
  • In this paper, forging of internal triangular and involute serrations are analyzed by upper bound method. Kinematically admissible velocity fields for half pitch of the serration were proposed. It was assumed that the shape flow surface during forging is a straight line perpendicular to plane of symmetry. Using the suggested velocity fields, forging loads and relative pressures were calculated by numerical method. Experiments were carride out with commercial AI 2024 aluminium alloy. As a result, the calculated solutions are good agreement with experimental results, so it is useful to predict the loads for forging of internal serrations.

  • PDF

Upper Bound Analysis for Forging of Circular Gears (원호 기어의 단조 상계해석)

  • 조해용;최재찬;최종웅;민규식;박형진
    • Proceedings of the Korean Society of Precision Engineering Conference
    • /
    • 1996.04a
    • /
    • pp.761-765
    • /
    • 1996
  • This paper describes the forging of circular tooth profiled gears as a series of development of simulator for non-axisymmetric parts that being used at the pump pulley, timing belt pulley etc. in automobiles. The half pitch of gear is divided into 6 deformation regious and kinematically admissible velocity fields for those regions are proposed. The neutral surface is introduced torepresent inner flow of material during forging operation with flat punch and, for each step, it is assumed as a circle. The upper bound solutions obtained from the suggested kinematically admissible velocity fields are in good agreement with experimental results and they are useful to predict the capacity of forging press for forging of circular gears.

  • PDF

The Study on the Tube Drawing Process with a Floating Plug (프로팅 프러그를 사용한 관재 인발가공에 관한 연구)

  • Choi, Jae-Chan;Jin, In-Tai
    • Journal of the Korean Society for Precision Engineering
    • /
    • v.5 no.4
    • /
    • pp.24-31
    • /
    • 1988
  • The Upper Bound Solution has been used to investigate the effect of the various parameters on the floating-plug tube-drawing precess. A kinematically admissible velocity field considering the change of the tube thickness is proposed for the deformation process. Taking into account the position of the plug in the deforming region, shear energy at entrance and exit, friction energy on contact area, homogeneous energy are calculated. The theoretical values in proposed velocity field are good agreement with experimental values, It is investigated that the tube thickness in the deforming region is changed slightly toward minimization of deforming energy and then the drawing stress in lower than the crawing stress in the velocity field that the tube thickness is uniform.

  • PDF

Study for Forging of Spline with Upper Bound Method (상계법을 이용한 스플라인 단조에 관한 연구)

  • 조해용;최재찬;최종웅;민규식
    • Proceedings of the Korean Society for Technology of Plasticity Conference
    • /
    • 1995.10a
    • /
    • pp.37-47
    • /
    • 1995
  • Forging of trapezoidal spline, serration and square spline with solid cylindrical billets and hollow one has been investigated by means of upper bound method. Kinematically admissible velocity fields for forging of splines have been proposed in this study. The half pitch of splines has been divided into deformation regons. The neutral surface is introduced into forging of splines with flat punch and, for each step, it is assumed as a circle with its radius rn upper bound solutions obtained obtained by proposed kinematically admissible velocity fields are useful to predict the loads for forging of splines.

  • PDF

Study on the curving phenomenon of sylinderical product in extrusion process (원형제품의 압출가공시 제품의 굽힘현상에 관한 연구)

  • 최재찬;진인태
    • Proceedings of the Korean Society for Technology of Plasticity Conference
    • /
    • 1995.10a
    • /
    • pp.136-142
    • /
    • 1995
  • The kinematically admissible velocity field is developed for the analysis of extruded products. The curving of product in extrusion is caused by the linearly distributed longitudinal velocity on the cross-section of the workpiece at the die exit. In the analysis, the longitudinal velocity in extrusion direction is divided into the uniform velocity and the deviated velocity. In order to satify the requirement of the kinematically admissible velocity field, the average value of the deviated velocity should be zero. At the same time, it should Iinearly change with the destance from the center of gravity of the cross-section of the workpiece. The results of the analysis show that the curvature of product incresses with increses in eccentricity of gravity center of the cross-section of workpiece at die entrance from that of the cross-sectio at the die exit.

  • PDF

Study on the Forging of Splines with Hollow and Solid Billets (중공 및 중실소재를 이용한 스플라인 단조에 관한 연구)

  • Cho, Hae-Yong;Choi, Jong-Ung;Min, Gyu-Sik
    • Journal of the Korean Society for Precision Engineering
    • /
    • v.13 no.1
    • /
    • pp.108-115
    • /
    • 1996
  • Forging of trapezoidal spline, serration and square spline with solid cylindrical billets and hollow one has been investigated by means of upper bound method. Kinematically admissible velocity fields for forging of splines have been proposed in this study. The half pitch of spline has been divided into several deformation regions. The neutral surface is introduced into forging of splines with flat punch and, for each step, it is assumed as a circle with its radius $r_n$. Upper bound solutions obtained by proposed kinematically admissible velocity fields are useful to predict the loads for forging of splines.

  • PDF

An Upper-Bound Analysis of the Socket Forming Process (Socket Forming에 관한 상계해석)

  • Hwang, Bum-Chul;Hong, Seung-Jin;Bae, Won-Byong
    • Journal of the Korean Society for Precision Engineering
    • /
    • v.17 no.8
    • /
    • pp.151-156
    • /
    • 2000
  • A kinematically-admissible velocity field is proposed to determine the forming load the average extruded length and the velocity distribution in the forward and backward extrusion process of a socket. Experiments are carried out with antimony-lead billets at room temperature using the rectangular punch and the hexagonal die. The theoretical predictions of the forming load and the average extruded length are in good agreement with the experimental results.

  • PDF

A UBET Analysis of the Extrusion/Forging Process of Trochoidally Headed Bars (트로코이드 형상의 머리를 가진 봉의 압출/단조에 관한 UBET해석)

  • Kim, Myung-Hun;Hong, Seung-Jin;Kim, Ho-Yoon;Bae, Won-Byong
    • Journal of the Korean Society for Precision Engineering
    • /
    • v.16 no.9
    • /
    • pp.96-103
    • /
    • 1999
  • A kinematically admissible velocity field is derived to analyze the forming load and the extruded length in the extrusion/forging process of trochoidally headed bars from round billets. The forming load and the extruded length are obtained by minimizing the total energy-consumption rate. Experiments are carried out with lead billets at room temperature using trochoidally shaped punches. The theoretical predictions of forming load and extruded length are in good agreement with the experimental results.

  • PDF

Plastic design of seismic resistant reinforced concrete frame

  • Montuori, Rosario;Muscati, Roberta
    • Earthquakes and Structures
    • /
    • v.8 no.1
    • /
    • pp.205-224
    • /
    • 2015
  • A new method for designing moment resisting concrete frames failing in a global mode is presented in this paper. Starting from the analysis of the typical collapse mechanisms of frames subjected to horizontal forces, the method is based on the application of the kinematic theorem of plastic collapse. The beam section properties are assumed to be known quantities, because they are designed to resist vertical loads. As a consequence, the unknowns of the design problem are the column sections. They are determined by means of design conditions expressing that the kinematically admissible multiplier of the horizontal forces corresponding to the global mechanism has to be the smallest among all kinematically admissible multipliers. In addition, the proposed design method includes the influence of second-order effects. In particular, second-order effects can play an important role in the seismic design and can be accounted for by means of the mechanism equilibrium curves of the analysed collapse mechanism. The practical application of the proposed methodology is herein presented with reference to the design of a multi-storey frame whose pattern of yielding is validated by means of push-over analysis.

Analysis for forging of trochoidal gears (트로코이드 기어의 단조 해석)

  • Cho, Hae Yong;Min, Gyu Sik;Choi, Jongung
    • Journal of the Korean Society for Precision Engineering
    • /
    • v.13 no.9
    • /
    • pp.77-83
    • /
    • 1996
  • This paper describes forging of trochoidal gears, which are being widely used in timing belt pulley, pump pulley etc., as a series of development of the simulator for non-axisymmetric elements. Kinematically admissible velocity fields for forging of trochoidal gear were proposed and the loads were calculated by numerical method. When the simulation was carried out, half pith of gear was divided into 6 deformation regions which have different velicity fields by assumptions and boundary conditions. The neutral surface was introduced into forging of trochoidal gears with flat punch and, for each step, it is assumed as a circle with its radius r$_{n}$. The experimental set-up was installed in 200 ton hydraulic press for forging. The billets, of A1 2218 aluminum alloy, were slightly phosphate-coated. It was shown that thd theoretical solutions, as upper bound, are useful to predict the forging load for forging of trochoidal gears, because thdt give estimates that are substantially higher than experimental loads.s.

  • PDF