二段多重変動振幅荷重下のスポット溶接継手の疲労寿命評価

抄録

In this paper, multi two step variable amplitude load fatigue testing of spot-welded joints was carried out, and experimental values and values obtained by minor’s rule were compared. In addition, similar fatigue testing in high-tensile steel sheet SPFC590 was performed, and the possibility of fatigue life estimation by using the nominal structural stress was examined. (1) The experimental values of the fatigue life were greater than the estimated value if n₂/n₁ ≧ 1000. It revealed experimentally that the factor was a delay phenomenon of the crack growth caused by peak load. (2) Fatigue test results of SPFC590 showed a different tendency from that of SPCE. The fatigue life is substantially constant when n₂/n₁ ≧ 100, and were close to the estimated value using the nominal structural stress.