単点引張りせん断スポット溶接継手の疲れ強さの統一的評価式

抄録

This study intends to make clear the effects of the properties of parent metal, specimen width, sheet thickness and nugget diameter on the initiation life and the propagation life of fatigue crack in singlespot-welded joint under tensile-shear load, and using these results to establish an empirical formula according to which the ΔL-N curve can be drawn.
The empirical formula obtained is expressed in the following equation.
ΔL=C(1+N/T₂)^m/(N/T₁)^m (kN)
here, m=0.25, C=0.1×W^0.22×t^0.91×d^0.61
Ti=10⁷×1/1-Y' T₂=10⁷×1-Y/3×t/0.8
Y=1.2×E1./100
ΔL: Load range (kN), N: Number of cycles (cycle), W: Specimen width (mm), t: Sheet thickness (mm), d: Nugget diameter (mm), E1.: Elongation of parent metal (%)
It was confirmed that accuracy of the empirical formula is at considerable high level, when this formula is applied for data of hitherto published many reports and obtained results are compared with their experimental ones.