THE ASYMPTOTIC STUDY OF FATIGUE-CRACK GROWTH BASED ON DAMAGE MECHANICS

In order to evaluate the mechanical behaviour around a growing fatigue crack tip for plane stress of mode I, the asymptotic governing equati ons and their boundary conditions are formulated by the light of damag e mechanics. A series of examples are studied numerically to obtain th e orders of stress, strain and damage, the distributions of the stress and damage field, and the contour of the process zone determined by a threshold condition for damage evolution. It is found that the stress has no (or very weak) singularity while the strain is less singular t han it is under traditional K-dominance, The conventional boundary con dition of a crack is substituted with the traction free requirement on V-notch surfaces. A Paris typed equation of crack growth is also deri ved as a result of present model.