抄録
Local strain at welded toes is the most critical factor in fatigue strength estimation of welded structures. The local strain approach was evaluated as an estimation method for fatigue strength of complicated structures. Pulsating fatigue tests were carried out for four types of bracket structures which transmit external forces to box structures and for two types of flanged pipe structures using mild steel (SS 41). The local strain was measured using small strain gauges bonded directly to the welded toes of highly stressed structure parts during the fatigue tests. The crack initiation life was defined at number of cycles till cracks became visible at the welded toe. All the data points fell in the scatter band of aΔσ(=E·Δε)-Nc curve. The local strain approach is very useful in analyzing the fatigue strength of welded structures, because it is independent of the structure types.
