Abstract:

Based on the study of the crack tip parameter in elastic plastic crack growth, further discussions on the high speed crack growth are given. A thermal elastic plastic coupled material model and an advanced method for calculating the incremental path independent integral are introduced. The characteristics of the crack tip integrals under different crack growth speeds and different situations, whether considering temperature and strain rate or not, are described. The distributions of stresses and strains in front of the crack tip and the development of plastic zone are also given. It is interesting to find that the expansion of the plastic zone during dynamic crack growth is non monotony. And it is concluded that the triaxiality stress parameter may control both steady crack growth and dynamic crack growth.

Key words: incremental path-independent integr al, hig h-speed cra ck g row th, crack-tip par ameter