2021 Fiscal Year Final Research Report
Dependence of Load Angle on Static Strength of Resistance Spot Welded Lap Joints
| Project/Area Number |
19K05080
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| Research Category |
Grant-in-Aid for Scientific Research (C)
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| Allocation Type | Multi-year Fund |
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| Section | 一般 |
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| Review Section |
Basic Section 26050:Material processing and microstructure control-related
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| Research Institution | Kyushu Institute of Technology |
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Principal Investigator |
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| Project Period (FY) |
2019-04-01 – 2022-03-31
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| Keywords | 抵抗スポット溶接 / 継手強度 / 複合荷重 / 高張力鋼板 / 荷重角度依存性 |
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| Outline of Final Research Achievements |
The dependence of joint strength on loading angle was investigated for resistance spot welded lap joints with steel plates of different base metal tensile strengths when loaded in the slant direction. As a result, it was found that the joint strength of all steel plates tended to decrease once and then increase after showing the lowest point as the loading angle increased. A method for accurately estimating the macroscopic deformation and stress of steel plates using FEM was also established. By using the macroscopic mechanical model, a strength evaluation method for resistance spot welded joints under combined loading was established. Furthermore, from the observation of the fracture surface and the stress distribution calculated by FEM, it was confirmed that the bending deformation of the steel plate is a factor that significantly influences the strength of the joint in steels with high base metal strength.
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| Free Research Field |
溶接力学
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| Academic Significance and Societal Importance of the Research Achievements |
抵抗スポット溶接された継手に引張せん断荷重や十字引張荷重が重畳した，いわゆる多軸応力が作用するような複合荷重下での強度についてはJISやISOなどの国内外の規格では規定がなく，ほとんど検討されていない．よって，荷重角度と継手強度の因果関係を示す因子は国内外ともに検討された例はほとんど無かった．また，斜め方向に引っ張る荷重の角度によっては規格で規定された引張せん断強度，十字引張強度より低い荷重で破断する実験結果を示した．この事実は溶接継手構造物の強度設計を見直す必要を示唆している．この強度低下要因，継手強度の荷重角度依存性を明らかにしたことが本研究の意義である．
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