Abstract:Shot peening (SP) is a controlled and systematic process of surface treatment that has a large number of controllable process parameters that make its application highly challenging. It involves the shooting of small and hard metallic balls at a targeted surface, with the aim of enhancing the fatigue strength of the workpiece under unfavorable service conditions. The compressive residual stress (CRS) induced by this application is expensive to evaluate experimentally. This paper presents a numerical model of t… Show more
“…The model chosen for this analysis is the Johnson-Cook (JC) plasticity model [29] due to its ease of dealing with high strain rates and dynamic simulations. The model formulates the Von Mises flow stress σ as per Equation (9), where ε p eff is the equivalent plastic strain, εp eff is the equivalent plastic strain rate, with C and ε0 being strain rate sensitivity coefficients. The strain-rate sensitivity is incorporated by defining the evolution of plastic strain by Equations (10 and 11), where R is a ratio of the strain rate yield stress to the static yield stress.…”
Section: Materials Modelmentioning
confidence: 99%
“…Therefore, when analysing the components of Equation (2), it is evident that the shot and workpiece mass, velocity, and material are essential parameters in determining the amount of resulting plastic deformation. Figure 1 Illustration indicating a single shot striking the surface of a workpiece, adapted from [9]. Plastic deformation of the shot will also occur if hardness is of similar value to the workpiece.…”
Section: Shot Peening Residual Stress and Fea Simulationmentioning
confidence: 99%
“…Figure 1. Illustration indicating a single shot striking the surface of a workpiece, adapted from[9]. Plastic deformation of the shot will also occur if hardness is of similar value to the workpiece.…”
ASTM F75 implants distort due to residual stress released after finishing machining operations, causing implants to fail quality requirements. Previous work has shown that a shot blasting cleaning process could be the source of this distortion. Finite element analysis (FEA) is conducted to predict stress and Almen strip arc heights for experimental comparison. 2D and 3D single impact models and 3D multiple impact models are created. 3D multiple impact models with plastically deforming shot are shown to accurately predict the stress state and distortion. For shot with hardness similar to the implants, distortion creating stress magnitudes are induced, with the greatest fluctuations in stress coming from shot velocity. The depth of the predicted compressive stress layer ranges from 0.23 to 0.6 mm.
“…The model chosen for this analysis is the Johnson-Cook (JC) plasticity model [29] due to its ease of dealing with high strain rates and dynamic simulations. The model formulates the Von Mises flow stress σ as per Equation (9), where ε p eff is the equivalent plastic strain, εp eff is the equivalent plastic strain rate, with C and ε0 being strain rate sensitivity coefficients. The strain-rate sensitivity is incorporated by defining the evolution of plastic strain by Equations (10 and 11), where R is a ratio of the strain rate yield stress to the static yield stress.…”
Section: Materials Modelmentioning
confidence: 99%
“…Therefore, when analysing the components of Equation (2), it is evident that the shot and workpiece mass, velocity, and material are essential parameters in determining the amount of resulting plastic deformation. Figure 1 Illustration indicating a single shot striking the surface of a workpiece, adapted from [9]. Plastic deformation of the shot will also occur if hardness is of similar value to the workpiece.…”
Section: Shot Peening Residual Stress and Fea Simulationmentioning
confidence: 99%
“…Figure 1. Illustration indicating a single shot striking the surface of a workpiece, adapted from[9]. Plastic deformation of the shot will also occur if hardness is of similar value to the workpiece.…”
ASTM F75 implants distort due to residual stress released after finishing machining operations, causing implants to fail quality requirements. Previous work has shown that a shot blasting cleaning process could be the source of this distortion. Finite element analysis (FEA) is conducted to predict stress and Almen strip arc heights for experimental comparison. 2D and 3D single impact models and 3D multiple impact models are created. 3D multiple impact models with plastically deforming shot are shown to accurately predict the stress state and distortion. For shot with hardness similar to the implants, distortion creating stress magnitudes are induced, with the greatest fluctuations in stress coming from shot velocity. The depth of the predicted compressive stress layer ranges from 0.23 to 0.6 mm.
“…The finite element (FE) method, one of the powerful methods for dynamic analysis, can be effectively adopted for simulating single shot impact over the target. In Finite element (FE) analysis, elastic-plastic behavior of the target after indentation with high velocity can be taken into account [10]. The relationships between shot specification and the resultant residual stress attributes can be compared.…”
In the present numerical study, the residual stresses generated during the shot peening process were evaluated using the finite element method. The influence of shot velocity on the residual stress distribution due to the indentation of a rigid shot over the target plate of alloy steel was studied. The finite element package ABAQUS 6.20 is used for simulating the shot peening process considering the target plate to be deformable. A parametric study was performed by introducing strain hardening rate as H1 = 800 MPa, keeping the dimension of target plate same with variation in shot velocity 20, 50, 75, 100, 125, and 150 m/s to check the behavior of residual stress distribution. As the indentation takes place over the metallic target plate, elastic-plastic deformation was observed. The indentation of the shot with a different velocity range causes the difference in the depth and size of the dent and induces the compressive residual stress. For perfectly plastic and the strain hardened material, the residual stress contour was simulated. The simulated results for strain hardened material show the significant change in the compressive residual stress in the sub-surface region of the target plate. It is evident from the results that the shot velocity has a significant effect on the residual stress distribution. The maximum compressive residual stress is achieved when the shot is indented at a velocity of 125 m/s.
“…Several authors used FEA or semi‐analytical models [ 14 ] to estimate the CoR values for different velocities and impacting angles to be used as input in DEM. [ 7,9,10,15 ] Alternatively, few authors determined CoRs experimentally using single‐shot experiments. [ 11,16,17 ] Fathallah et al [ 16 ] recorded the velocities of several shots during shot‐peening of a manganese steel using a non‐contact optical device.…”
Instrumented single‐shot experiments provide crucial information of a material's response to impact events that can be used in shot‐peening modelling. However, no authors successfully used such test for constitutive model identification and validation as existing test rig generally cannot provide an accurate determination of the shot trajectory in three dimensions over a wide velocity range. In this work, a shot‐peening test rig that can propel single shot under the process conditions with a high aiming accuracy is presented. The test rig propels industrial shot by sudden pressurised gas release. A methodology to recover the propelled shot three‐dimensional trajectory within a 200‐μm accuracy using two high‐frequency cameras is developed in an open‐source in‐house code. The test rig can propel 0.5‐, 1.19‐ and 2.5‐mm‐diameter shot at velocity ranging from 0.8 to 143 m s−1 and can send several shots at the same position when using the largest shot diameter. Two potential applications of the set‐up are presented for (i) coefficient of restitution measurement with different shooting angles and velocities and (ii) crystal plasticity finite element model validation using the impact dent topology, the shot displacement curve and the crystal misorientation field under the dent.
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