• Title/Summary/Keyword: Corner Radius

Search Result 127, Processing Time 0.024 seconds

The Spinnability of Multi-step Cylindrical Cup in Spinning Process (스피닝 공정을 이용한 다단 원형 컵 형상의 성형성에 관한 연구)

  • 박중언;한창수;최석우;김승수;나경환
    • Proceedings of the Korean Society of Precision Engineering Conference
    • /
    • 2001.04a
    • /
    • pp.1016-1020
    • /
    • 2001
  • The spinning is a very effective manufacturing technology for short production runs in a variety of sizes and shapes, because it can form the cross-section or tubular parts various shapes. However extensive experimental and analytical research has not been carried out. In this study, and fundamental experiment was conducted to improve productivity with process parameter such as tool path, angle of roller holder(a), feed rate(v) and corner radius of forming roller(Rr). These factors were selected as variables in the experiment because they were most likely expected to have and effect on spring back. The clearance was controlled in order to achieve the precision product which is comparable to deep drawing one. And also thickness and diameter distribution of a multistage cup obtained by shear spinning process were observed and compared with those of a commercial product produced by conventional deep drawing.

  • PDF

Experimental Study on the Flow Behind an Axisymmetric Backward-Facing Step (축대칭 하향단 흐름에 대한 실험적 연구)

  • 김경천;부정숙;양종필
    • Transactions of the Korean Society of Mechanical Engineers
    • /
    • v.18 no.9
    • /
    • pp.2463-2476
    • /
    • 1994
  • Local mean fluctuating velocity components were measured in the separating and reattaching axisymmetrc region of turbulent boundary layer over the wall of convex cylinders placed in a water tunnel by using 2-color 4-beam fiber optics laser Doppler velocimetry. Measurements were made with three different diameters of cylinders with four different diameters of cylinders with four different diameter of the obstructions. The range of Reynolds number based on step height was between 5,000 to 25,200. The study demonstrates that the reattachment length decreases with decreasing cylinder radius and is always shorter than that for the two-dimensional backward-facing step flow at the condition of the same step height. It was also observed that the turbulent kinetic energy in the recirculating region increases with an increases in the radius of convex curvature. The measured velocity field suggests that the transverse curvature can effect definitely the formation of corner eddy.

Failure Analysis of Connecting Rod at Small End (커넥팅로드 소단부 파단의 해석)

  • 민동균;전병희;김낙수
    • Transactions of the Korean Society of Mechanical Engineers
    • /
    • v.19 no.2
    • /
    • pp.382-390
    • /
    • 1995
  • Failure of connecting rod in automotive engine may cause catastrophic situation. The corner radius at small end has an effect on stress raising. To investigate the stress distribution in connecting rod during operation, the finite element analysis was used by giving possible maximum tension and compression. Excessive sizing after forging connecting rod may result in the tensile residual stress which lower the fatigue life and cause premature failures. It was shown that when the sizing amount is too large, the location of high tensile residual stress coincide with that of high stress amplitude during operation through the elastic-plastic finite element analysis. The endurance limit moves down due to the surface finish and decarburization, which combines with the movement of resultant stress points to dangerous range. It was concluded that the precise control of sizing and enough corner radius are necessary to a reliability of connecting rod.

The Effect of Die Design and Process Condition in Precision Forging for AI7075 Alloy(l) (AI7075합금의 정밀단조시 금형설계와 단조조건의 영향(l)-실험과 상계해석을 중심으로-)

  • 이영선;이정환;정형식;이상용;이동원
    • Proceedings of the Korean Society for Technology of Plasticity Conference
    • /
    • 1996.10a
    • /
    • pp.105-112
    • /
    • 1996
  • Aluminium alloy have been used extensively as forging materials for aircraft components due to their high specific strength and corrosion resistance. A large portions of these materials are used as airframe components consisted of various combination of such Rib-Web structure. But the problem of high forging pressure and defect which were caused by narrow Rib thickness prevented from the favorable developments and laboratory scaled trials. In this study, optimization of forging variables such as corner radius and temperature in Rib-Wed structure were established. The 2 mm of corner radius minimized the forging pressure to get the fixed Rib height, which well coincided with theoretical result according to Upper-Bound analysis. And optimum workpiece temperature was below 450$^{\circ}C$ in consideration of grain growth and forging defects by local melting.

  • PDF

The Effect of Die Design and Process Condition in Precision Forging for AI7075 (ll) (AI7075합금의 정밀단조시 금형설계와 단조조건의 영향(ll) -유한요소해석을 중심으로-)

  • 이영선;이정환;이상용
    • Proceedings of the Korean Society for Technology of Plasticity Conference
    • /
    • 1996.10a
    • /
    • pp.113-121
    • /
    • 1996
  • AI7075 alloy has been used for aircraft components since it has the advantage of high strength, high toughness, and high corrosion resistance. Many airframe components consist of various combinations of rib-web structure. In this study, various process paramenters such as die design, lubricant, ram speed, forging temperature have been investigated using the experiment and F.E.M. simulation to develop the precision forging technology for AI7075. When lubricant is applied to both material and die, shear friction factor is 0.1 which shows best effect of lubricant. It is specific corner radius of die that minimized forging load regarding process conditions, especially according to the ratio of the width of rib and web. In conclusion, optimum corner radius is 2~3mm when the width of rib and web is 3mm and 20mm respectively.

  • PDF

Forming Characterististics of Radial-Backward Extrusion for Single Action Pressing (단동 프레싱에 의한 레이디얼-후방압출의 성형특성)

  • Jang, Dong-Hwan;Ko, Beong-Du;Lee, Yeong-Sub;Hwang, Beong-Bok
    • Journal of the Korean Society for Precision Engineering
    • /
    • v.18 no.10
    • /
    • pp.76-83
    • /
    • 2001
  • This paper is concerned with the analysis of the forming characteristics of radial-backward extrusion. The single action pressing is analyzed by using the rigid-plastic FEM. The design factors such as die corner radius, gap height, and friction factor are involved in the simulation. The analysis is focused on the influences of the design factors on the maximum punch farce and metal flow into can and flange region. As a result of analysis, the gap height among the design factors is known to have a major effect on the metal flow of radial-backward extrusion for single action pressing compared with other design factors. As is expected, forming load and volume of flange increase as gap height and die corner radius increase, respectively.

  • PDF

Analysis of Parameters Affecting on Durability of CID Filter using Numerical Method (수치적 접근을 통한 CID필터 형상이 내력에 미치는 영향 분석 연구)

  • Bui, V.H.;Kim, S.M.;Ku, T.W.;Kim, J.;Kang, B.S.
    • Proceedings of the Korean Society for Technology of Plasticity Conference
    • /
    • 2008.05a
    • /
    • pp.391-394
    • /
    • 2008
  • Durability of product is an important technical parameter of a current interception device (CID) filter. This parameter is influenced by several factors, such as: environment condition, external force, shape of device, heat and so on. In this study, the effect of the geometry of the device on durability was carried out. The effect of shape on durability of device is presented by force-carrying capacity that a device can sustain a maximum external force. Studied parameters of the CID filter's geometry include clearance, thickness, and corner radius. Fracture criterion of Cockcroft and Latham was also used to predict the maximum force-carrying capacity of device.

  • PDF

The Effects of the Process and Die Design for Precision Forging of Al Alloys (AI 합금 정밀단조를 위한 금형설계 및 공정조건의 영향)

  • Lee, Young-Seon;Lee, Jung-Hwan
    • Journal of the Korean Society for Precision Engineering
    • /
    • v.16 no.11
    • /
    • pp.166-173
    • /
    • 1999
  • Al forged parts are many cases with rib-web section which is difficult to manufacture precisely. Therefore, process conditions must be optimized for precision forging of Al alloys. In this study, various process parameters such as die design, lubricant, ram speed, forging temperature have been investigated using the experiment, upper bound theory and F.E.M. simulation to develop the precision forging technology for rib-web shape component. When lubricant is applied to both material and die, shear friction factor is 0.1 which shows best effect of lubricant. It is specific corner radius of die that minimized forging load regarding process conditions, especially according to the ratio of the width of rib and web. In conclusion, optimum corner radius is 2~3mm when the width of rib and web is 3mm and 20mm respectively.

  • PDF

A Study on Strain Relief in a Square Cup Drawing (정사각용기 성형에서 변형률완화에 관한 연구 1)

  • Kim, Jin-Moo;You, Ho-Young
    • Journal of the Korean Society for Precision Engineering
    • /
    • v.16 no.2 s.95
    • /
    • pp.31-38
    • /
    • 1999
  • Square cups have been drawn to 20mm~60mm in depth and displacements and strains have been analysed by FEM and experiment. Displacements and strains on the corner flange of square cups have been compared with those of cylindrical cups. The results have shown that shear strains take place on corner flanges of square cups, it is necessary to adopt effective strain for comparing of stains and the effective strains on the corner flange in square cups are smaller than those in cylindrical ones.

  • PDF

Processing Speed Improvement of Software for Automatic Corner Radius Analysis of Laminate Composite using CUDA (CUDA를 이용한 적층 복합재 구조물 코너 부의 자동 구조 해석 소프트웨어의 처리 속도 향상)

  • Hyeon, Ju-Ha;Kang, Moon-Hyae;Moon, Yong-Ho;Ha, Seok-Wun
    • Journal of Convergence for Information Technology
    • /
    • v.9 no.7
    • /
    • pp.33-40
    • /
    • 2019
  • As aerospace industry has been activated recently, it is required to commercialize composite analysis software. Until now, commercial software has been mainly used for analyzing composites, but it has been difficult to use due to high price and limited functions. In order to solve this problem, automatic analysis software for both in-plane and corner radius strength, which are all made on-line and generalized, has recently been developed. However, these have the disadvantage that they can not be analyzed simultaneously with multiple failure criteria. In this paper, we propose a method to greatly improve the processing speed while simultaneously handling the analysis of multiple failure criteria using a parallel processing platform that only works with a GPU equipped with a CUDA core. We have obtained satisfactory results when the analysis speed is experimented on the vast structure data.