Abstract
A large number of tiny particles, which is less than 200 µm in diameter, hit the specimen simultaneously for the surface modification in Fine Particle Peening (FPP) treatments. For the fatigue resistance, it is important to induce the higher compressive stress at the surface. In FPP treatment, the induced compressive residual stress is influenced by many parameters such as material properties, particle size, nozzle distance, air pressure and so on. We focused on the material hardness and investigated the effect of hardness ratio between a shot particle and a specimen on the plastic dissipation energy and the compressive residual stress in the specimen. FPP treatment is very complex and it is quite difficult to observe the local phenomena in experiments. Thus, numerical simulations were employed in this study. The obtained results show that the hardness ratio is the dominant parameter for the plastic dissipation in the specimen. As the hardness ratio increases, the kinetic energy of shot particles effectively transfers into the plastic dissipation in the specimen and the higher compressive residual stress is induced in the specimen.
