The fatigue life prediction for structure with surface scratch considering cutting residual stress, initial plasticity damage and fatigue damage

• A new method to predict the fatigue life of scratched components is proposed.
• The initial plasticity damage and fatigue damage are considered in the method.
• The numerical dynamic analysis is conducted to simulate the cutting process.
• The calculated result of fatigue damage is compared with the experimental result.

In this paper, a continuum damage mechanics based fatigue model is used to evaluate the effect of surface scratches resulting from accidental scrapes on the fatigue life of structures. First, a dynamic analysis is conducted to simulate scratch generation. Second, the initial damage field caused by plastic deformation in the scraping process is calculated. Third, for structures with scratches under fatigue loading, Chaudonneret’s damage model for multiaxial fatigue is applied and the finite element implementation is presented. At last, this method is applied to life calculation for scratched specimens and for a scratched fixed plate. The theoretical calculation tallies with the experimental results.