Fatigue Life of Multi-Lap Welding of Automotives Steel Sheet by QSTS

2008 ◽  
Vol 33-37 ◽  
pp. 151-156
Author(s):  
Seung Chul Shin ◽  
Sung Mo Yang ◽  
Hyo Sun Yu ◽  
Hee Yong Kang ◽  
Chae Won Kim
Keyword(s):  
Life Cycle ◽  
Fatigue Life ◽  
Welded Joints ◽  
Fuel Efficiency ◽  
Life Extension ◽  
Steel Sheets ◽  
Whole Process ◽  
Lap Welding ◽  
Automotive Steel ◽  
Spot Welded

This paper shows how the number of lap of spot welded joints in automotive steel sheets changes the life -cycle transform of itself. There has been significant developments in the life extension of automotive steel sheets, as well as in passenger safety. We verified the validity of the S-N curve of materials by QSTS test. Moreover, we used EZNCEN and HS40R, which are commonly used as automotive steel sheets because of their excellence in increasing fuel efficiency. The purpose of research was to compare the fatigue life of multi - lap of spot welded joints to there. In addition s, we used the two different kinds of sheets together in the same welding under the same condition. Through this whole process, the hypothesis on the life cycle of lethargy coefficients was found to be in good agreement with the result of the experiment. That is, when using sheets of the same materials in one welding, the fatigue life of two laps of a spot welded joint was found to be much superior by EZNCEN 5~14%, HS40R 17~30%,and when using each sheet of different materials, we found the decrease in fatigue life by 6~16%. Finally, the best value from the data was chosen based on the experiment for the analysis of the fatigue life of each layer.

scholarly journals Correction: Wang et al. Generalized SCF Formula of Out-Of-Plane Gusset Welded Joints and Assessment of Fatigue Life Extension by Additional Weld. Materials 2021, 14, 1249

Materials ◽  
2021 ◽  
Vol 14 (9) ◽  
pp. 2331
Author(s):  
Yixun Wang ◽  
Yuxiao Luo ◽  
Yuki Kotani ◽  
Seiichiro Tsutsumi
Keyword(s):  
Fatigue Life ◽  
Welded Joints ◽  
Life Extension ◽  
Out Of Plane

The authors wish to revise in the text of Appendix A, pages 19–21 [...]

scholarly journals Generalized SCF Formula of Out-Of-Plane Gusset Welded Joints and Assessment of Fatigue Life Extension by Additional Weld

Materials ◽  
2021 ◽  
Vol 14 (5) ◽  
pp. 1249
Author(s):  
Yixun Wang ◽  
Yuxiao Luo ◽  
Yuki Kotani ◽  
Seiichiro Tsutsumi
Keyword(s):  
Fatigue Life ◽  
Fatigue Resistance ◽  
Welded Joints ◽  
Life Extension ◽  
Leg Length ◽  
Notch Stress ◽  
Out Of Plane ◽  
Weld Toe ◽  
Effective Notch Stress ◽  
Geometric Effects

The existing S-N curves by effective notch stress to assess the fatigue life of gusset welded joints can result in reduced accuracy due to the oversimplification of bead geometries. The present work proposes the parametric formulae of stress concentration factor (SCF) for as-welded gusset joints based on the spline model, by which the effective notch stress can be accurately calculated for fatigue resistance assessment. The spline model is also modified to make it applicable to the additional weld. The fatigue resistance of as-welded and additional-welded specimens is assessed considering the geometric effects and weld profiles. The results show that the error of SCFs by the proposed formulae is proven to be smaller than 5%. The additional weld can increase the fatigue life by as great as 9.4 times, mainly because the increasing weld toe radius and weld leg length lead to the smaller SCF. The proposed series of S-N curves, considering different SCFs, can be used to assess the welded joints with various geometric parameters and weld profiles.

Fatigue Life of Multi-Spot Welded Structures

2007 ◽  
Vol 348-349 ◽  
pp. 249-252
Author(s):  
Pietro Salvini ◽  
Francesco Vivio ◽  
Vincenzo Vullo
Keyword(s):  
Fatigue Life ◽  
Numerical Solution ◽  
Welded Joints ◽  
Structural Model ◽  
Fatigue Behaviour ◽  
Progressive Damage ◽  
Welded Structures ◽  
Accumulated Damage ◽  
Fatigue Data ◽  
Spot Welded

A procedure that makes use of a conventional stress value (ERS) is applied to spot welded joints. The ERS can be evaluated for every spot weld of the structural model. Through the use of ERS-N curves, fatigue data performed on different joint geometries can be successfully mixed together. One of the main aspects is that progressive damage deeply influences fatigue behaviour, so that a simple numerical solution neglecting accumulated damage is unable to foresee the whole fatigue life. In the present paper the method has been applied to many experimental results: it is shown that a unique criterion is able to deal with several different structures and materials.

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