Fatigue crack growth under compressive loading

Abstract Fatigue cracks were grown in centre-notched sheet made from BS4360 50B structural steel. Despite the fact that loading was fully compressive, cracks initiated and grew in regions of residual tensile stress at the notch roots. It was observed that crack growth rates decreased with increasing crack length until arrest occurred. Near tip strain gauges were used to monitor crack closure; closure readings agreed well with those deduced from growth rates. The residual stress ahead of the slit tip and normal to the slit plane, σres, was estimated from the crack growth rate response. It was found that σres scaled with distance, x , from the slit tip as σ res αx −0.56 .