3D shear-mode fatigue crack growth in maraging steel

Fatigue crack growth tests in mixed-mode II + III were performed on maraging steel using an assymmetric four point bending device and the 3D evolutions of the crack fronts -measured by SEM after interrupted testswere analyzed, taking into account the reduction in effective crack driving force by the interlocking and friction of the asperities of the crack surface. The crack growth rates were found to correlate best with 2 eff III 2 eff II K 2 . 1 K ∆ + ∆ .