Fatigue Behavior of Spot Welds under Variable-Amplitude Loading 850369
This paper presents data and methods for predicting fatigue lives of spot welds subjected to variable amplitude random-sequence load fluctuations. An equivalence between the fatigue behavior of spot welds under constant amplitude and under variable-amplitude cyclic-load fluctuations is also established by using an effective damage-parameter range approach.
The analyses presented show that the damage parameter for fatigue of spot welds is where ΔP and ΔθN are the fluctuations in the applied stress and in the nugget rotation respectively. The analyses also show that the effective damage-parameter range derived by using the Miner cumulative damage law, EMiner', resulted in an excellent correlation of fatigue lives for spot welds under variable-amplitude and constant-amplitude cyclic loading. The root-mean-square, RMS, damage-parameter range, resulted in a conservative correlation.