VOID GROWTH AHEAD OF A DOMINANT CRACK IN A MATERIAL WHICH DEFORMS BY COBLE CREEP

This paper examines the process of void growth ahead of a dominant crack in a material which deforms by grain-boundary diffusion. A numerical technique recently developed by the authors is used to analyse the full interaction between void growth and deformation ahead of the crack tip. For the situation where voids only grow within a narrow zone directly ahead of the crack tip, it is possible to develop a range of simple analytical models. It is demonstrated that for this class of problem a suitable utilization of the dislocation model suggested by Thouless provides a good estimation of the void growth rate.