FATIGUE-CRACK INITIATION LIFE PREDICTION IN HIGH-STRENGTH STRUCTURAL-STEEL WELDED-JOINTS

The local approach method is used to calculate the fatigue crack initi ation/early crack growth lives (N-i) in high strength structural steel weldments. Weld-toe geometries, welding residual stresses and HAZ (he at affected zone) cyclic mechanical properties are taken into account in the N-i estimation procedure. Fatigue crack initiation lives are ca lculated from either a Basquin type or a Manson-Coffin type equation. The local (HAZ) stress and strain amplitudes and the local mean stress are determined from an analysis based on the Neuber rule and the Mols ki-Glinka energy approach. The accuracy of the different methods is ev aluated and discussed. Finally the previous methods are used with HAZ cyclic mechanical properties estimated from hardness measurements.