Estimating the fatigue crack initiation life of welds

摘要: The fatigue crack initiation life (cycles to obtain a 0.25-mm crack) was estimated for butt welds using strain-controlled concepts. Key developments which facilitated these estimates were the assumption of(K f ) m x conditions (the largest value of Kf possible given weld shape), use computer simulation methods modeled cyclic hardening and softening as well mean stress relaxation effects, properties actual zone in initial notch located. found be very sensitive changes Kf, but rather insensitive strength level. importance residual stresses varied with material did fraction total devoted initiation. Mild steel (ASTM Specification Structural Steel (A 36)) high strength, low alloy High-Yield Strength, Quenched Tempered Alloy Plate, Suitable Welding 514)) aluminum considered.