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 equations and their boundary conditions are formulated by the light of damage mechanics. A series of examples are studied numerically to obtain the 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 than it is under traditional K-dominance, The conventional boundary condition of a crack is substituted with the traction free requirement on V-notch surfaces. A Paris typed equation of crack growth is also derived as a result of present model.