Synergistic evolution mechanism of residual stress field and deformation in aero-engine thin-walled blades under service conditions

The surface state achieved through surface modification process is inherently unstable, and the evolution of surface integrity during service significantly impacts the performance of aero-engine blades. This study systematically investigated the surface integrity and deformation behavior of aero-engine blades by shot peening at different service stages. Experimental results indicated that the surface integrity of the blades underwent a sudden change within 10³ cycles, followed by a stable evolution phase, exhibiting notable spatiotemporal discreteness. Specifically, distinct evolutionary patterns were observed between the blade root and tip, the back and basin, and along the chord and height directions, leading to differential evolution in position and profile tolerances. Through vibration simulation, it was revealed that the discrete distribution of working stress was the primary cause of the spatiotemporal discreteness in surface integrity evolution. Based on linear elastic theory, the deformation behavior of the blades was shown to follow directional and relative criteria. Furthermore, a deformation prediction model for in-service blades (NS-FEM) was established, which introduces "net stress" as the driving load for deformation and avoids the damage to the blades caused by residual stress testing. The relative error of the NS-FEM model in predicting blade position was less than 15%. This study not only enhances the understanding of blade deformation behavior during service but also provides a methodological reference for the non-destructive prediction and online control of blade machining deformation.