Influences of material mismatch on interface crack tip field in three layered creeping materials

Interface creep cracking is very common to be seen in various kinds of welded components which are used widely in engineering practice. In the present paper, the interface creep crack tip field by considering material mismatch effect is studied. The interface creep crack is found to be close to the HRR field which can produce the faster creep crack growth rate. A material mismatch constraint parameter is proposed based on the validation of the local mismatch effect on the interface creep crack tip field which also maintains the self-similarity. An averaged material mismatch constraint M _avg ^∗ is presented to represent the material mismatch constraint effect. It reveals that the material mismatch constraint effect for interface creep crack decreases with the increase of the local mismatch factor. The physical meaning of the material mismatch constraint effect for the interface creep crack and its future application to engineering failure analysis is also discussed and presented.