• Title, Summary, Keyword: SPR joint

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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
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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.

Design of self-piercing rivet to joint in advanced high strength steel and aluminium alloy sheets (초고장력강과 알루미늄 합금의 접합을 위한 SPR 설계)

  • Kim, Dongbum;Qiu, Yuangen;Cho, Hae-Yong
    • Journal of Welding and Joining
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    • v.33 no.3
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    • pp.75-80
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    • 2015
  • Self-piercing riveting is an joining method of advanced high strength steels (AHSS) and other dissimilar materials. It has attracted considerable interest from the automotive industry. The SPR has become an interesting alternative joining technique for difficult to weld materials such as steels and aluminium alloys. In this paper, self-piercing rivet and anvil for SPR were designed for the joining conditions with AHSS and aluminium alloy. Various conditions of SPR were simulated for the design of rivets and anvils. The simulated results were in good agreement with experimental ones. As a result, over HV500 rivet is desirable to joint SPFC780 AHSS and aluminum alloy.

Fatigue Assessment Using SPR and Adhesive on Dissimilar Materials (SPR 과 접착제를 이용한 이종재료 접합의 피로평가)

  • Kim, Tae-Hyun;Suh, Jeong;Kang, Hee-Shin;Lee, Young-Shin;Park, Chun-Dal
    • Journal of the Korean Society for Precision Engineering
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    • v.28 no.10
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    • pp.1204-1209
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    • 2011
  • In this study, fatigue life is evaluated by comparing with lighter car body through the experiment on SPR joints. An experimental activity on sheet metal samples of Aluminum 5J32 and Steel SPRC440 has been conducted to achieve better understanding of the process. In addition, SPR joint used less than the existing Spot Welding improves joint strength and fatigue life is evaluated by using SPR and adhesive joining Hybrid. Joining(bonding) strength and fatigue life on SPR and Hybrid (SPR + adhesive) are evaluated throughout the experiment. With joining strength than 20 % of the aluminum material, dissimilar materials has improved over 2 times as large as the strength In case of dissimilar materials, the fatigue life of aluminum is increased by 1.6 to 2.5 times as large as the life.

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.

Fatigue Strength Evaluation of Self-Piercing Riveted Al 5052-H32 Joints under Mixed Mode Loading Conditions (혼합모드상태에서의 Al 5052-H32 셀프 피어싱 리벳 접합부의 피로강도 평가)

  • Kwak, Jin Gu;Kang, Se Hyung;Kim, Ho Kyung
    • Journal of the Korean Society of Safety
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    • v.31 no.3
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    • pp.1-7
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    • 2016
  • In this study, static and fatigue tests on the self-piercing riveted (SPR) joint were conducted using cross-shaped specimens with aluminum alloy (Al-5052) sheets. Mixed mode loading was achieved by changing the loading angles of 0, 45, and 90 degrees using a special fixture to evaluate the static and fatigue strengths of the SPR joints under mixed mode loading conditions. Simulations of the specimens at three loading angles were carried out using the finite element code ABAQUS. The fatigue specimens failed in an interfacial mode where a crack initiated at the upper sheet and propagated along the longitudinal direction and finally fractured Maximum principal stress, von-Mises effective stress failed to correlate the fatigue lifetimes at three loading angles. However, the equivalent stress intensity factor was found to be appropriate to correlate the fatigue lifetimes at three loading angles.

Fatigue Strength of Al-5052 Tensile-Shear Specimens using a SPR Joining Method (SPR 접합법을 이용한 Al-5052 인장-전단 시험편의 피로강도)

  • Lee, Man Suk;Kim, Taek Young;Kang, Se Hyung;Kim, Ho Kyung
    • Journal of the Korean Society of Safety
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    • v.29 no.4
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    • pp.9-14
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    • 2014
  • Self-piercing riveting(SPR) is a mechanical fastening technique which is put pressure on the rivet for joining the sheets. Unlike a spot welding, SPR joining does not make the harmful gas and $CO_2$ and needs less energy consumption. In this study, static and fatigue tests were conducted using tensile-shear specimens with Al-5052 plates for evaluation of fatigue strength of the SPR joints. During SPR joining process for the specimen, using the current sheet thickness and a rivet, the optimal applied punching force was found to be 21 kN. And, the maximum static strength of the specimen produced at the optimal punching force was 3430 N. During the fatigue tests for the specimens, interface failure mode occurred on the top substrate close to the rivet head in the most high-loading range region, but on the bottom substrate close to the rivet tail in the low -loading range region. There was a relationship between applied load amplitude $P_{amp}$ and lifetime of cycle N for the tensile-shear, $P_{amp}=3395.5{\times}N^{-0.078}$. Using the stress-strain curve of the Al-5052 from tensile test, the simulations for fatigue specimens have been carried out using the implicit finite element code ABAQUS. The relation between von-Mises equivalent stress amplitude and number of cycles was found to be ${\sigma}_{eq}=514.7{\times}N^{-0.033}$.

A coupled finite element/meshfreemoving boundary method for self-piercing riveting simulation

  • Cai, Wayne;Wang, Hui-Ping;Wu, C.T.
    • Interaction and multiscale mechanics
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    • v.6 no.2
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    • pp.257-270
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    • 2013
  • The use of lightweight materials has been steadily increasing in the automotive industry, and presents new challenges to material joining. Among many joining processes, self-piercing riveting (SPR) is particularly promising for joining lightweight materials (such as aluminum alloys) and dissimilar materials (such as steel to Al, and metal to polymer). However, to establish a process window for optimal joint performance, it often requires a long trial-and-error testing of the SPR process. This is because current state of the art in numerical analysis still cannot effectively resolve the problems of severe material distortion and separation in the SPR simulation. This paper presents a coupled meshfree/finite element with a moving boundary algorithm to overcome these numerical difficulties. The simulation results are compared with physical measurements to demonstrate the effectiveness of the present method.

Tensile-Shear Fatigue Strength of Self-Piercing Rivets Joining Dissimilar Metal Sheets (이종재료 Self-Piercing Rivets 접합부의 인장-전단 피로강도)

  • Kang, Se Hyung;Kim, Taek Young;Oh, Man Jin;Kim, Ho Kyung
    • Journal of the Korean Society of Safety
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    • v.30 no.4
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    • pp.1-7
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    • 2015
  • Self-piercing riveting (SPR) process is gaining popularity due to its many advantages. The SPR does not require a pre-drilled hole and has capability to join a wide range of similar or dissimilar materials and combinations of materials. This study investigated the fatigue strength of self-piercing rivet joint with aluminum alloy (Al-5052) and steel (SPCC) sheets. Static and fatigue tests on tensile-shear specimens were conducted. From the static strength aspect, the optimal punching force for the specimen with upper SPCC (U.S) sheet and lower aluminum alloy(L.A) sheets was 34 kN. During static test the specimens fractured in pull-out fracture mode due to influence of plastic deformation of joining area. There was a relationship between applied load amplitude $P_{amp}$ and number of cycles N ; $P_{amp}=19588N_f^{-0.211}$ and $P_{amp}=4885N_f^{-0.083}$ for U.S-L.A and U.A-L.S specimens, respectively. U.A-L.S fatigue specimens failed due to fretting crack initiation around the rivet neck between upper and lower sheets.

Fatigue Strength Evaluation of Self-Piercing Riveted Al-5052 Joints (셀프 피어싱 리베팅한 Al-5052 접합부의 피로강도 평가)

  • Kang, Se Hyung;Hwang, Jae Hyun;Kim, Ho Kyung
    • Journal of the Korean Society of Safety
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    • v.30 no.3
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    • pp.1-6
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    • 2015
  • Self-piercing riveting (SPR) is receiving more recognition as a possible and effective solution for joining automotive body panels and structures, particularly for aluminum parts and dissimilar parts. In this study, static strength and fatigue tests were conducted using coach-peel and cross-tension specimens with Al-5052 plates for evaluation of fatigue strength of the SPR joints. For the static experiment results, the fracture modes are classified into pull-out fracture due to influence of plastic deformation of joining area. During the fatigue tests for the coach-peel and cross-tension specimens with Al-5052, interface failure mode occurred on the top substrate close to the rivet head in the most cycle region. There were relationship between applied load amplitude $P_{amp}$ and life time of cycle N, $P_{amp}=715.5{\times}N^{-0.166}$ and $P_{amp}=1967.3{\times}N^{-0.162}$ were for the coach-peel and cross- tension specimens, respectively. The finite element analysis results for specimens were adopted for the parameters of fatigue lifetime prediction. The relation between SWT fatigue parameter and number of cycles was found to be $SWT=192.8N_f^{-0.44}$.

Mechanical fastening and joining technologies to using multi mixed materials of car body (차체 소재 다변화에 따른 체결 및 접합기술)

  • Kim, Yong;Park, Ki-Young;Kwak, Sung-Bok
    • Journal of Welding and Joining
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    • v.33 no.3
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    • pp.12-18
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    • 2015
  • The ultimate goal of developing body is revealed the "lightweight" at latest EuroCarBody conference 2012 and the most core technology is joining process to make lightweight car body design. Accordingly, in this study, the car body assembly line for the assembly process applies to any introduction, particularly in the assembly of aluminum alloy and composite materials applied by the process for the introductory approached. Process were largely classified by welding (laser, arc, resistance, and friction stir welding), bonding (epoxy bonding) and mechanical fastening (FDS, SPR, Bolting and clinching). Applications for each process issues in the case and the applicable award was presented, based on the absolute strength of the test specimens and joining characteristics for comparative analysis were summarized. Finally, through this paper, we would tried to establish the characteristics of the joint for lightweight structure.