Residual stress near single shot peening impingements determined by nanoindentation and numerical simulations

Abstract

The near-surface hardness and residual stresses resulting from a single shot peening impingement on aluminum alloy 2024-T351 were assessed by nanoindentation with spatial mapping of mechanical properties on cross sections through an impingement. For residual stress, a procedure was developed to couple nanoindentation experiments with numerical simulations for better understanding and predicting the effects of shot peening. A surface preparation method was developed that exposes the cross section of a single shot impingement for nanoindentation tests, while at the same time obtaining accurate measurements of the impingement dimensions. Starting parameters for the numerical simulation in terms of shot diameter and the shot velocity were selected to best match measurements of the impingement depth and diameter. The experimental results indicated that the greatest hardness was located at the nearest indent to the peened surface, whereas the maximum compressive residual stress was located sub-surface. When comparing experimental and numerical residual stresses, the experimental results showed a greater maximum compressive residual stress that was in closer proximity to the peened surface. Overall, residual stress fields compared between experimental and numerical results were similar, and differences could be explained in terms of the effect of strain hardening. The current work demonstrated the usefulness of coupling nanoindentation experiments with numerical simulations for evaluating the surface modifications resulting from a single shot peening impingement.

Dynamic finite element analysis of shot peening process of 2618-T61 aluminium alloy

“…The steel shot resulted in 180 m dimple diameter with approximately 20.0 m depth. The pro le, dimple diameter, and impingement depth obtained for steel shot are comparable with those presented in [4], where a ceramic shot of diameter 450 m is impacted at 54 m/s on an aluminium AA2024-T35 plate. In [4], the impingement diameter and depth obtained numerically were within 3% of that measured experimentally.…”

“…In the numerical analyses of shot peening process [2][3][4], the target plate is usually de ned as a deformable body and the shot as a rigid body. However, in real-world applications, both the shot and plate behave as deformable bodies.…”

“…In the literature, there exist extensive experimental studies for the assessment of important properties related to the shot peening process, e.g. plastic deformation; residual stress distribution; fatigue life; and the e ect of shot, target, and process parameters [4][5][6][7].…”

Literature review of numerical simulation and optimisation of the shot peening process

“…Different material models are used for the elastoplastic target materials with different materialhardening behaviours, typically isotropic, 21,23,35,44 kinematic [45][46][47] and combined isotropic and kinematic hardening. 41,48,49 The isotropic model is employed for materials whose yield surface size changes uniformly in different directions so that the corresponding yield stresses change when plastic deformation occurs. It should be noted that isotropic models are generally appropriate where the DEM in this table means using flowing particles for generation of shots/projectiles.…”

A Numerical Investigation of a Single-Shot in a DEM-FEM Approach to Shot Peening Simulation

“…With regard to the effects of peening parameters, Mann et al [18] used a calibrated numerical single-shot via a nano-indentation experiment to study the near-surface hardness and residual stress, which resulted in the prediction of shot peening-induced residual stresses for an aluminum alloy. Hong et al [15,19] used a single-shot impact on a metallic component to investigate the effects of the various peening parameters on the residual stress distribution.…”