• Title/Summary/Keyword: tube hydro-forming

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Hydro-forming Process of Automotive Engine Cradle by Computer Aided Engineering (CAE) (컴퓨터 시뮬레이션(CAE)을 이용한 자동차용 엔진 크레들의 하이드로-포밍 공정 연구)

  • Kim, Kee-Joo;Choi, Byung-Ik;Sung, Chang-Won
    • Transactions of the Korean Society of Automotive Engineers
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    • v.16 no.1
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    • pp.86-92
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    • 2008
  • Recently, the use of tubes in the manufacturing of the automobile parts has increased and therefore many automotive manufactures have tried to use hydro-forming technology. The hydro-forming technology may cause many advantages to automotive applications in terms of better structural integrity of the parts, lower cost from fewer part count, material saving, weight reduction, lower spring-back, improved strength and durability and design flexibility. In this study, the whole process of front engine cradle (or front sub-frame) parts development by tube hydro-forming using steel material having tensile strength of 440MPa grade is presented. At the part design stage, it requires feasibility study and process design aided by CAE (Computer Aided Design) to confirm hydro-formability in details. Effects of parameters such as internal pressure, axial feeding and geometry shape on automotive sub-frame by hydro-forming process were carefully investigated. Overall possibility of hydro-formable sub-frame parts could be examined by cross sectional analyses. Moreover, it is essential to ensure the formability of tube material on every forming step such as pre-bending, preforming and hydro-forming. At the die design stage, all the components of prototyping tools are designed and interference with press is examined from the point of geometry and thinning.

A study on the hydro-embedding technology in the tube hydroforming process (하이드로포밍 공정을 이용한 무용접 부품체결 기술개발에 관한 연구)

  • 김동규;박광수;안익태;한수식;문영훈
    • Proceedings of the Korean Society for Technology of Plasticity Conference
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    • 2003.10a
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    • pp.241-244
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    • 2003
  • The productivity of hydroforming process can be increased by combining pre-forming process and post-forming process such as the bending, piercing and the embedding process. Therefore in this study, integrated studies on the hydro-embedding technology have been performed by analyzing the deformed mode of the tubes and the optimal process parameters. In the case of the embedding test the characteristics of the embedded parts, such as the shape of the screw tip, screw thread and shape of thread were investigated at various process conditions. To measure the clamping force between the embedded part and the tube, special measuring device was used.

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Effects of Process Parameters owl the Tube Hydroformability (하이드로포밍 성형성에 미치는 공정인자 영향도 해석)

  • 김봉준;김정운;문영훈
    • Transactions of Materials Processing
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    • v.11 no.1
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    • pp.54-60
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    • 2002
  • The purpose of the present paper is to investigate the effect of Process parameters such as internal pressure, amount of axial feeding, and frictional condition between the die and the material on the tube hydro-formability. For carbon steel tubes(STKM 12A, STBH 410 and SPS 290), simple bulging, circular bulging and Tee-fitting tests are performed to evaluate the hydro-formability of these materials which is determined by deformation characteristics such as thickness distribution, forming height and branch dome shape. The formabilities obtained from these tests are analysed and compared with the results of the numerical simulation.

Crash Performance Evaluation of Hydro-formed Automotive DP-Steel Tube Considering Welding Heat Effects (용접부의 영향을 고려한 하이드로포밍된 자동차용 DP강관의 충돌 특성 평가)

  • Chung, K.H.;Kwon, H.S.;Park, S.H.;Ro, D.S.;Chung, K.
    • Transactions of Materials Processing
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    • v.15 no.8 s.89
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    • pp.568-573
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    • 2006
  • In order to numerically evaluate automotive hydro-formed DP-steel tubes on crash performance considering welding heat effects, the finite element simulations of crash behavior were performed for hydro-formed tubes with and without heat treatment effects. This work involves the mechanical characterization of the base material and the HAG-welded zone as well as finite element simulations of the crash test of hydro-formed tubes with welded brackets and hydro-forming of tubes. The welding heat effects on the crash performance are evaluated in efforts to improve the process optimization procedure of the engine cradle in the design stage. In particular, FEM simulations on indentations have been performed and experimentally verified for material properties of weld zone and heat affected zone.

Prediction of Shape Accuracy in Elastomer-Forming of a Cylindrical Tube by a Response Surface Method (반응표면법을 이용한 실린더 튜브 고탄성체 성형의 형상 정확도 예측)

  • Kim, K.T.;Lee, G.A.;Choi, S.;Lee, H.W.;Lee, Y.S.
    • Transactions of Materials Processing
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    • v.17 no.3
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    • pp.218-224
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    • 2008
  • A recent trend in automotive parts has been an integration of sub-assemblies with unified shapes. Tube structures also have been integrated to one body structure by using a near net shape forming instead of adopting welding. A cylindrical elastomer-forming process can be utilized to form a steel tube compressed in a radial direction. This process has some advantages compared to a hydro-forming or a swaging process in the viewpoint of a lower investment and a higher productivity. In order to predict a feasible specification of products within a work capability of the elastomer-forming equipment developed previously, effects of geometrical parameters of a tube on its shape accuracy are examined. Two characteristic parameters to account for the shape accuracy are chosen. One is the curvature radius at the corner part and the other is the straight ratio of the formed region. Careful examination of two parameters has led that the shape accuracy can be easily predicted by the regression equation obtained from the response surface method.

Effect of heat treatment conditions on the tube hydroformability (하이드로 포밍 공정시 관재의 열처리 조건에 따른 성형성 분석)

  • Park, K.S.;Kang, B.H.;Kim, D.K.;Moon, Y.H.
    • Proceedings of the KSME Conference
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    • 2003.11a
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    • pp.1810-1815
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    • 2003
  • Tube hydroforming provides a number of advantages over conventional stamping process, including fewer secondary operation, weight reduction, assembly simplification, adaptability to forming of complex structural components and improved structural strength and stiffness. In this study, the effect of the heat treatment on the hydro-formability has been investigated. By using the mild steel tube bulging test is performed at various heat treatment conditions to evaluate the hydro-formability.

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Experimental Studies of the Forming Process for the Tubular Hydroforming Technology (관재 하이드로 포밍에 의한 성형 공정의 실험적 연구)

  • 김성태;임성언;이택근;김영석
    • Transactions of Materials Processing
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    • v.9 no.1
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    • pp.35-42
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    • 2000
  • In this paper, we developed the hydroforming simulator which can apply an axial compressive force and high internal pressure to bulge a tube. Experimental dtudies have been performed to investigate the effect of each parameters such as internal pressure and axial compression stroke required for the forming of circular components. Under the improper forming conditions there were two forming failures. One was the axial buckling due to excessive axial compressive load and the other was the circumferential necking fracture due to relatively high internal pressure. A safe forming zone without any failures exists between these two extreme zones. Also the condition of forming failure such as fracture is examined throughout the theoretical analysis. This paper covers a brief overview of the mechanism of hydroforming process as well as the design of die and tools.

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Studies on the Shape Optimization of Connecting Element for Hydro-Embedding (하이드로 임베딩시 체결용 연결요소의 형상 최적화 연구)

  • Kim B. J.;Kim D. K.;Kim D. J.;Moon Y. H.
    • Transactions of Materials Processing
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    • v.14 no.9 s.81
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    • pp.756-763
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    • 2005
  • The applicability and productivity of hydroforming process can be increased by combining pre- and post-forming processes such as the bending, piercing and embedding process. For the fabrication of automotive parts, the hollow bodies with connecting nuts are widely used to connect parts together. Hollow body with connecting nuts has been conventionally fabricated by welding nuts or screwing in autobody screws. It requires multiple steps and devices fur the welding and/or screwing Therefore in this study, hydro-embedding process that combines the hydraulic embedding of connecting element(nut) with hydroforming process is investigated. Studies on the hydro-embedding technology have been performed to optimize the shape of the connecting element by analyzing the deformed mode of the embedded tube The effects of the shape of the screw tip, screw thread and shape of thread on the connection force between the tube and the connecting element have been investigated to optimize the shape of connecting element. Finite element analysis has also been performed to provide deformation behaviors of the tube surrounding a hole produced by hydro-embedding.

Finite element study on the hydro-embedding process (유한요소 해석법을 이용한 하이드로 임베딩 공정연구)

  • Kim D. K.;Park K. S.;Kim D. H.;Moon Y. S.
    • Proceedings of the Korean Society for Technology of Plasticity Conference
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    • 2004.05a
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    • pp.206-209
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    • 2004
  • In the hydroforming process the number of process can be reduced by combining pre-forming process and post-forming process such as the bending, piercing and the embedding process. Integrated studies on the embedding manufacturing technology have been performed by analyzing the deformed mode of the tubes and the optimal process parameters. In this study, a simulation model that can prove clamping force between the clamping element and tube has been investigated by FEM. The characteristics of the embedded parts, such as the shape of the screw tip, screw thread and shape of thread were investigated at various clamping element conditions.

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