Effects of ring indentation, punching, and shot peening treatments on fatigue crack retardation considering modified J-integrals: A comparative study

In the present research, the authors tried to investigate effects of different Severe Plastic Deformation (SPD) processes on the crack growth rate of Aluminum ally. To this end, Finite Element (FE) simulation was performed for ring identification, punching, and shot peening treatments. Then, validation of the Finite Element Model (FEM) for each process was done using the technique of comparing the results with the achievements of other researchers. Also, redistribution of residual stresses around the Plane Crack (PLC) was predicted with good accuracy using FE-path technique. After that, FE-Cell methodology was used to compare the real residual stress redistribution around PLCs in fatigue test specimen. The results showed that ring indentation had the effect of infiltrating more Compressive Residual Stresses (CRS) around the PLC (shot peening: 0≤t≤0.8mm, punching: 0≤t≤2.8mm, and ring indentation: 0≤t≤3.3mm), while the maximum CRS was created by the shot peening treatment (approximately 50% more than the other two methods). As a result, among different SPD treatments, ring indentation was introduced as a better fatigue crack retarder. To prove this statement, by calculating the net values of tensile and compressive stresses in each increment of short crack growth, the average of the corrected J-integrals was obtained. Finally, a short crack growth cycle number was determined using the Paris rule, and the results obtained for all cases were compared. © 2025 Elsevier Ltd