• Title, Summary, Keyword: 액압성형

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Forming Limit Diagram of an Aluminum Tube from Hydroforming tests (액압성형 시험을 통한 알루미늄 튜브 재료의 성형한계도)

  • Kim J. S.;Lee J. K.;Park J. Y.;Lee D. J.;Kim H. Y.;Kim H. J.
    • Proceedings of the Korean Society for Technology of Plasticity Conference
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    • pp.253-257
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    • 2005
  • A tube hydroformability testing system was designed and fabricated so as to observe the forming process and to apply forming condition along arbitrarily pre-programmed internal pressure-axial feed path. The forming limit diagram of A6063 extruded tube, of 40.6 mm outer diameter and 2.25 mm thickness, was successfully obtained through free bulging and T-forming tests except the region of high positive minor strain. It is found that the data points marked on the FLD are mostly located near the strain paths from the finite element analysis excluding the cases of large axial feed. There exist data points even in the area beyond the uniaxial tension mode, since the reduction in thickness decreases due to the axial feed. The forming limit from T-forming test was considerably lower than that from free bulge test. It seems because the deformation is localized at the pole.

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Bursting Failure Prediction in Tube Hydroforming Process (튜브 액압성형 공정에서의 터짐 현상 예측)

  • Kim, Jeong;Lei, Liping;Kang, Sung-Jong;Kang, Beom-Soo
    • Transactions of the Korean Society of Automotive Engineers
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    • v.9 no.6
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    • pp.160-169
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    • 2001
  • To predict busting failure in tubular hydroforming, the criteria for ductile fracture proposed by Oyane is combined with the finite element method. From the histories of stress and strain in each element obtained from finite element analysis, the fracture initiation site is predicted by mean of the criterion. The prediction by the ductile fracture criterion is applied to three hydroforming processes such as a tee extrusion, an automobile rear axle housing and lower am. For these products, the ductile fracture integral I is not only affected by the process parameters, but also by preforming processes. All the simulation results show the combination of the finite element analysis and the ductile fracture criteria is useful in the prediction of farming limit in hydroforming processes.

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Finite Element Analysis of Axisymmetric Sheet Hydroforming Processes (축대칭 박판 액압성형 공정의 유한요소 해석)

  • Jeong, Y. H.;Lee, S. H.;Keum, Y. T.
    • Proceedings of the Korean Society for Technology of Plasticity Conference
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    • pp.26-29
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    • 1999
  • The sectional forming analysis program for analyzing the hydroforming processes of axisymmetric sheet parts was tleveloped. The rigid-viscoplastic FEM formulation based on membrane theory was derived, wh~cta simi~ltaneously solve force equilibrium as well as non-penetration condition. Hill's non-quadratic normal anisotropic yield theory(1979) was used for material behaviour. For describing the liquid pressure iaction, the flexible tool concept was introduced. Isotropic hardening law was also assumed. To verify the \,alidity of the formulation, the stepped cup forming process as well as the hydrostatic bulging test were \imnlated. Simulation results agreed well with Finckenstein and experimental ones.

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판재성형의 유한요소해석

  • 강정진;오수익;정영철;박종진
    • Journal of the Korean Society for Precision Engineering
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    • v.17 no.4
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    • pp.38-47
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    • 2000
  • Recently, finite element method has been used as an effective tool in the design process of sheet metal forming. In the present study, an implicit method and an explicit method have been developed for 2D analysis and 3D analysis, respectively, and applied to several processes including plane strain draw bending and TWB sqaure cup drawing. Also, commercial codes are used for geometrically complex problems, such as tube hydroforming, "L" cup deep drawing and side frame forming. In this paper, basic formulations used in the methods are introduced and results obtained from the applications are discussed.discussed.

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Experimental Studies on Formability and Characteristics of Tube Hydroforming (관재 액압성형에 의한 성형성 및 성형품 특성에 관한 실험적 연구)

  • Jo Y. J.;Son H. S.;Park C. D.;Kim Y. S.
    • Proceedings of the Korean Society for Technology of Plasticity Conference
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    • pp.54-57
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    • 2001
  • Hydroforming is core production techniques for the super light weight and high safety of the vehicle body. In order to establish and understand hydroforming, the tube hydroforming simulator which could control an axial compression and high internal pressure with computer operation was developed in tube bulging. This paper presents experimental investigation for process parameters, such as Internal pressure and axial compression. In addition, the mechanical properties, such as strain hardening and energy absorption ability of hydroformed part, is discussed.

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Derivation of Loading Conditions for Tube Hydroforming Process using Adaptive Method (Adaptive 방법을 이용한 관재액압성형조건 도출)

  • Heo, Seong-Chan;Kim, Jeong;Kang, Beom-Soo
    • Proceedings of the KSME Conference
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    • pp.642-647
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    • 2007
  • Determination of loading conditions for tube hydroforming(THF) process that implies an amount of the increment in axial feeding and internal pressure for each step is one of the most important constituents at the process design level. On account of the fact that those design factors mentioned above are imposed simultaneously during the process, suitable loading conditions are required to obtain robust products without any failure such as buckling, necking, bursting and so on. In which, especially, bursting is well known as the most frequently occurred failure in general THF process. In this study, therefore, determination of the loading condition based on the adaptive method was carried out to obtain safe loading paths. In addition, forming limit curves are applied to evaluate the derived loading conditions by using the simulation results. Consequently, it is found that described method in this study for THF process design is useful and has a feasibility.

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The Study of Roll-forming Technology for UHSS Hydroformed Parts (UHSS 하이드로포밍 개발을 위한 박육관의 롤 포밍 기술 연구)

  • Park, Sungpill;Kwon, Yongjai
    • Transactions of the Korean Society of Automotive Engineers
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    • v.23 no.1
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    • pp.41-48
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    • 2015
  • In the automotive industry, it is required to reduce weight of the car and improve fuel efficiency. Competitive pricing is also a very important issue. That's why application of welded steel tube is increasing in order to produce a vehicle with a competitive price. Also, hydroforming technology is asking more and more for thinner tubing to realize to a lighter vehicle design. Steel tube is produced through a multi-stage process called roll forming. In that case, bucking and work hardening should be considered key forming technology is to prevent buckling and minimize work hardening during steel tubing for hydroforming To prevent buckling, it is required to optimize forming process in order to minimize stretching in edge sections and hold tightly cross-section during welding. And to minimize work hardening, it is needed to know the proper process to avoid reforming.