Effect of Crack Position on Slant Crack Growth in Fretting Fatigue
Toru KIMURA and Kenkichi SATO
Abstract:It is well known that fretting fatigue cracks usually initiate in the contact area near contact edge and grow obliquely to the normal direction of the contact surface. In order to determine the fretting fatigue crack growth mechanism, the stress intensity factors KI and KII have been widely used. The authors have established a scheme and software to obtain the values of KI and KII of the oblique fretting fatigue cracks which are initiated at the contact edge and subjected to arbitrarily distributed contact pressure with friction. In this paper, the solution has been expanded to the fretting fatigue cracks initiated near contact edge. The calculated results of stress intensity factors show that the distance between crack position and contact edge markedly affects on the values of KI and KII. Crack propagation direction has been estimated by using maximum tensile stress (MTS) criterion according to the calculated values of KI and KII. The effect of mode II stress intensity factor KII due to normal and tangential stress distributions near the contact edge on the crack propagation direction has been discussed. It has been concluded from the present study that the slant crack growth in fretting fatigue results from crack initiation near contact edge. Key Words:Fretting fatigue, Stress intensity factor, Principle of superposition, Slant crack, Crack propagation direction, Maximum tensile stress criterion