Effect of shot peening on <i>J</i>-integral and crack propagation rate of semi-elliptic surface crack on Ti6Al4V

Abstract

Considering the residual stress, residual strain and residual strain energy, the influence of shot peening on the J-integral parameters of semi-elliptic surface crack front was quantitatively calculated and analyzed. The shot peening process was simulated, the fatigue crack was generated by changing the constraint condition and far field load was applied to calculate the J-integral and crack propagation rate. The effect of semi-elliptic surface cracks with different depth and different shot velocities on fracture parameters was analyzed. The results show that when shot velocity is a certain value, the reduction of the J-integral value after shot peening decreases with the increase of the crack depth compared with that without shot peening, which indicates that shot peening is more beneficial to suppress the fatigue crack propagation. When the crack depth is 0.3mm, the J-integral value of the deepest point of the crack front reduces from 4.25N/mm to 2.99N/mm, and the reduction is about 30.1%.The J-integral value decreases with the increase of shot velocity when crack depth is a certain value,therefore,increasing shot velocity is more beneficial to retard the fatigue crack propagation.

Keywords

• shot peening
• residual stress
• <i>J</i>-integral
• Ti6Al4V
• semi-elliptic surface crack