Feasibility of hammer peening for straightening of bent turbine rotor after operation based on finite element analysis

This study investigates the applicability of hammer peening for straightening bending deformation in power-generation turbine rotors using a combined experimental and finite element analysis (FEA) approach. A simplified cylindrical rotor specimen was fabricated, and bending deformation was intentionally induced through sequential hammer peening. Subsequent peening was applied in the opposite direction to correct the induced deformation. After each peening stage, run-out measurements were conducted to evaluate changes in rotor deformation. A corresponding finite element model was developed, and multi-impact simulations were performed under the same conditions as the experiments. The predicted deformation behavior was compared with eccentricity values calculated from the experimental run-out data. The results showed that the numerical model reproduced the deformation trends and spatial distribution of eccentricity observed in the experiments. The prediction error at the maximum eccentricity locations remained within approximately 3.0–7.5% across all impact stages. In addition, the deformation induced during the initial stages was reduced after the final peening stage, indicating the progressive straightening effect of repeated impacts. These findings demonstrate that the proposed numerical approach provides a quantitative framework for predicting deformation behavior during hammer peening and can be used to evaluate rotor straightening processes.