• Title/Summary/Keyword: 피어싱

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Finite element analysis of unconstrained axisymmetric piercing (구속이 없는 축대칭 피어싱 공정의 유한요소해석)

  • 양동열;유요한;이종수
    • Transactions of the Korean Society of Mechanical Engineers
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    • v.10 no.6
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    • pp.876-888
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    • 1986
  • The Study is concerned with the analysis of unconstrained axisymmetric piercing as a nonsteady forging process by the rigid-plastic finite element method. In the numerical analysis of axisymmetric piercing, the initial velocity field is generated by assuming the material as a linear viscous material to begin with in order to facilitate the input handling and to ensure better convergencey. The strain-hardening effect for nonsteady deformation and the friction of the die-material interial interface are considered in the formulation. Rigid body treatment is also incorporated in the developed program. The experiments are carried out for aluminum alloy specimens (A1204) with different specimen heights. It is shown that the experimental results are in excellent agreement with the finite element simulations is deformed configuration. For load prediction the theoretical prediction shows excellent agreement with th eexperimental laod in the initial stage of loading before fracture of the specimen is not initiated. Distribution of stresses, strains and strain rates has been found for the given cases in computation. On this basis several fracture criteria are introduced in order to check the fracture initiation. It is found that maximum shear criterion is capable of good fracture prediciton.

Analysis for Realization of Vertical Wall in Holes by Applying Alternate High Pressure in the Punchless Piercing Process (무 펀치 피어싱 공정에서 교번식 고압 적용을 통한 구멍 내 직벽 구현 해석)

  • Lee, Sang-Wook;Um, Tai-Joon;Joo, Young-Cheol;Kim, Kug-Weon;Kwon, Kye-Si
    • Journal of the Korea Academia-Industrial cooperation Society
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    • v.10 no.5
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    • pp.929-934
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    • 2009
  • In this work, the punchless piercing process with application of alternate high pressure has been proposed as a method to obtain pierced holes having nearly vertical wall over thin metal plates. The numerical simulation considering Lemaitre damage model has been accomplished for the proposed method. The simulated results have been compared with those by conventional one-way punch less piercing process. It has been revealed that the fractured section made by pressure alternation method shows nearly steep wall where the deviation angle from the vertical line is as small as $3.6^{\circ}$.

Optimization Analysis for Realization of Vertical Wall in the Punchless Piercing Process (무 펀치 피어싱 공정에서 직벽 구현을 위한 최적화 해석)

  • Lee, Sang-Wook;Um, Tai-Joon;Joo, Young-Cheol;Kim, Kug-Weon;Kwon, Kye-Si
    • Journal of the Korea Academia-Industrial cooperation Society
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    • v.11 no.1
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    • pp.7-12
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    • 2010
  • In this work, optimization analysis has been accomplished to find important process factors for realization of vertical wall around holes punched by the punchless piercing process. Taguchi method was used for optimization analysis. Lemaitre damage theory, one of the ductile fracture models, was also adopted to simulate numerically formation of vertical wall. From the results of analysis the most influencing factor that affects the vertical wall has been revealed to be 'Corner Radius of Die'.

Assessment of Fatigue Life on Curved Self-Piercing Rivet Joint Specimen (곡률을 갖는 셀프-피어싱 리벳 접합시편의 피로수명 평가)

  • Kim, Min-Gun;Cho, Seok-Swoo;Kim, Dong-Youl
    • Journal of the Korean Society of Manufacturing Technology Engineers
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    • v.19 no.1
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    • pp.71-79
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    • 2010
  • One of methods that accomplish fuel-efficient vehicle is to reduce the overall vehicle weight by using aluminum structure typically for cross members, rails and panels in body and chassis. For aluminum structures, the use of Self Piercing Rivet(SPR) is a relatively new joining technique in automotive manufacture. To predict SPR fatigue life, fatigue behavior of SPR connections needs to be investigated experimentally and numerically. Tests and simulations on lap-shear specimen with various material combinations are performed to obtain the joining strength and the fatigue life of SPR connections. A Finite element model of the SPR specimen is developed by using a FEMFAT SPR pre-processor. The fatigue lives of SPR specimens with the curvature are predicted using a FEMFAT 4.4e based on the liner finite element analysis.

Investigating the Tensile-Shear of Dissimilar Materials Joined Using the Hybrid SPR Technique (Hybrid SPR 접합을 적용한 이종소재 인장전단에 관한 연구)

  • Yu, Kwan-jong;Choi, Du-bok;Kim, Jae-yeol
    • Journal of the Korean Society of Manufacturing Process Engineers
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    • v.19 no.9
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    • pp.33-39
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    • 2020
  • Self-piercing rivets are often used in the automotive industry, among other industries, as mechanical components to join multiple materials such as aluminum alloys. Self-piercing rivets have a strong sealing property, although there is considerable scope for their performance improvement. In this study, to enhance the performance of self-piercing rivets, the hybrid self-piercing riveting (SPR) technique, using the existing SPR and structural adhesive, was proposed. Moreover, heterogeneous material specimens subjected to the hybrid SPR technique were manufactured and tested. The joint strength of the test pieces of different materials was evaluated through finite element analyses.

An Automated Die Design System for Blanking and Piercing of Stator and Rotor Parts (스테이터 및 로터의 블랭킹 및 피어싱에 관한 자동화된 금형설게 시스템)

  • Park, J.C.;Kim, B.M.;Kim, C.
    • Journal of the Korean Society for Precision Engineering
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    • v.14 no.5
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    • pp.22-33
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    • 1997
  • This paper describes a research work of developing a computer-aided design of blanking and piercing for stator and rotor parts. Based on knowledge-based rules, the die design system, STRTDES2, is designed by considering several factors, such as complexities of blank geometry and punch profile, and availability of press equipment and standard parts. Therefore this system can carry out a die design for each process which is obtained from the result of an automated process planning system, STRTDES1 and generate part drawing and the assembly drawing of die set in graphic forms. Knowledges for die layout are extracted from plasticity theories, relevant references and empirical know-hows of experts in blanking industries.

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A Comparative Analysis between 2D and 3D Modeling in the Piercing Process of Lead Frame and Experimental Study (리드프레임 피어싱 공정의 2D와 3D 모델링 비교해석 및 실험적 연구)

  • Bang, H.J.;Han, S.S.;Han, C.H.
    • Proceedings of the Korean Society for Technology of Plasticity Conference
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    • 2006.05a
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    • pp.288-291
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    • 2006
  • Piercing or blanking process is widely used to manufacture most of lead frame parts, but it is difficult to analyze the real process by the actual shape through progressive dies. In this paper several stages in progressive punching are modeled by 2D and 3D configurations using $DEFORM^{TM}$ 2D/ 3D code. During the progressive stage some state variables and deformed configurations are analyzed in each model. There are three stages in the process, the deformations at each stage are cumulative. The advantages and disadvantages of these two type modeling are discussed and analyzed. The experiments are performed as a working material copper alloy through manufactured die. Computed results in load by two types are compared to experiments.

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Assessment of Structural Stiffness and Fatigue Life in Self-Piercing Rivet(SPR) Joint of Car Body (차체 셀프-피어싱 리벳 접합의 구조강성 및 피로수명 평가)

  • Kim Min-gun;Lee Kun-chan;Lee Byung-jun
    • Transactions of the Korean Society of Mechanical Engineers A
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    • v.28 no.8 s.227
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    • pp.1174-1182
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    • 2004
  • Recently, Self Piercing Rivet(SPR) has been spotlighted in the automotive industry as a substitutive resort of spot welding and has also been watched by the designer as lightening a car body due to their superior assembly processes. Fatigue behavior of SPR joint needs to be investigated experimentally and numerically to predict its structural stiffness and fatigue life. Testing of lap-shear specimens with various material combinations is performed to obtain the joining strength and the fatigue life of SPR connections. The simulation of SPR lap-shear specimens is also conducted to obtain the structural stiffness of SPR connections under different material combinations. A Finite element model of the SPR lap-shear specimen is developed using a FEMFAT SPR pre-processor. The fatigue lift of SPR specimen is predicted using a FEMFAT 4.4e based on the liner finite element analysis.