AN ASYMPTOTIC ANALYSIS TO A TENSILE CRACK IN CREEPING SOLIDS COUPLED WITH DAMAGE .2. LARGE DAMAGE REGION VERY NEAR THE CRACK-TIP

A coordinate perturbation approach is used to deal with the asymptotic behavior of damage in the region very near the tip of a static mode I crack in creeping solids. Like Part I, the damage effect here is also incorporated into the power-law viscous creep constitutive equations by using the strain equivalence principle and the evolution of the cum ulative damage is described by the multi-axial Kachanov-Rabotnov kinet ics equation. The equation derived poses a nonlinear eigenvalue proble m which has to be solved by numerical approaches. The solution obtaine d enables one to realize how the damage has effect on the crack tip fi eld and what manner stresses vary with when the crack tip is quite clo sely approached. Examples are given to illustrate the distributions of stresses, strains and damage. (C) 1997 Elsevier Science Ltd.