• Title/Summary/Keyword: 소성숏

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3D FE Model with FEA Factors and Plastic Shots for Residual Stress Under Oblique Shot Peening (경사충돌 피닝잔류응력에 미치는 해석인자의 영향 및 소성숏이 포함된 3차원 유한요소모델)

  • Lee, Bae-Hwa;Kim, Tae-Hyung;Lee, Hyung-Yil
    • Transactions of the Korean Society of Mechanical Engineers A
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    • v.34 no.3
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    • pp.323-331
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    • 2010
  • In this study, we propose a 3D finite element (FE) model for the residual stress under oblique shot peening. Using the FE model for an oblique impact, we examine the effects of factors on the residual stress such as the Rayleigh damping in the material, dynamic friction, and the rate dependency of the material and systematically integrate the effects. The plastic deformation of the shot is also emphasized. Then, the FE model is used to study oblique multi-impacts. The results obtained using the FE model are compared with experimental x-ray diffraction (XRD) results; in contrast to the rigid and elastic shots, plastic shots are found to produce residual stresses similar to that shown in the XRD results. Thus, the 3D FE models with integrated factors and plastically deformable shots are validated. The proposed model will serve as a basis for the 3D FE model for multi-impacts with different impact angles to simulate the actual phenomenon of shot peening.

Area-Averaged Solution of Peening Residual Stress Using a 3D Multi-impact Symmetry-cell FE Model with Plastic Shots (소성숏이 포함된 3차원 다중충돌 대칭-셀 해석모델을 이용한 면적평균 피닝잔류응력해)

  • Kim, Tae-Hyung;Lee, Hyung-Yil
    • Transactions of the Korean Society of Mechanical Engineers A
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    • v.33 no.4
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    • pp.310-320
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    • 2009
  • In this paper, we estimate area-averaged solution of peening residual stress using a 3-D multi-impact symmetry-cell FE model. The symmetry-cell model includes factors reflecting peening phenomena and plastic shot. Area-averaged solution is much closer to XRD experimental solution than 4-node-averaged solution in plastic shot FE model. We then obtain FE Almen saturation curve corresponding to experimental Almen curve based on area-averaged solution. Using the curve, we obtain FE area-averaged solution in major peening materials, and compare the FE solution with experimental solution. In peening materials, surface, maximum compressive residual stress and deformation depth reach experimental solutions. Thus, FE Almen curve is useful for estimation of residual stress solution and could improve the efficiency of peening process. Consequently, it is confirmed that concept of area-averaged solution is the realistic analytical method for evaluation of peening residual stress.

A 2D FE Model for a Unique Residual Stress in Single Shot Impact (단일 숏 충돌에서의 잔류응력 유일해를 위한 2차원 유한요소해석 모델)

  • Kim, Tae-Hyung;Lee, Hyung-Yil
    • Proceedings of the KSME Conference
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    • 2007.05a
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    • pp.183-188
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    • 2007
  • In this paper, we propose a 2D-FE model in single impact with combined physical factors to obtain a unique residual stress by shot peening. Applied physical parameters include elastic-plastic deformation of shot ball, material damping coefficients, strain rate, dynamic friction coefficients. Single impact FE model consists of 2D axisymmetric elements. The FE model with combined factors showed converged and unique distributions of surface stress, maximum compressive residual stress and deformation depth. Further, in contrast to the FE models with rigid shot and elastic deformable shot, FE model with plastic deformable shot produces residual stresses very close to experimental solutions by X-ray diffraction. We therefore validated the 2D FE model with combined peeing factors and plastic deformable shot. This FE model will be a base of the 3D FE model for residual stresses by multi-impact shot peening.

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A 2D FE Model for Unique Solution of Peening Residual Stress in Single Shot Impact (단일 숏 충돌시 피닝잔류응력 유일해를 위한 2차원 유한요소해석 모델)

  • Kim, Tae-Hyung;Lee, Hyung-Yil
    • Transactions of the Korean Society of Mechanical Engineers A
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    • v.32 no.4
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    • pp.362-370
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    • 2008
  • In this paper, we propose a 2D-FE model in single impact with combined physical factors to obtain a unique residual stress by shot peening. Applied physical parameters consist of elastic-plastic deformation of shot ball, material damping coefficients, strain rate, dynamic friction coefficients. As a kinematical parameter, there is impact velocity. Single impact FE model consists of 2D axisymmetric elements. The FE model with combined factors showed converged and unique distributions of surface stress, maximum compressive residual stress and deformation depth. Further, in contrast to the FE models with rigid shot and elastic deformable shot, FE model with plastic deformable shot produces residual stresses very close to experimental solutions by X-ray diffraction. We therefore validated the 2D FE model with combined peening factors and plastic deformable shot. This FE model will be a base of the 3D FE model for residual stresses by multi-impact shot peening.

A Optimal 3D FE Model for Evaluation of Peening Residual Stress Under Angled Multi-impacts (다중경사충돌시 피닝잔류응력 평가를 위한 최적의 3차원 유한요소모델)

  • Hyun, Hong-Chul;Kim, Tae-Hyung;Lee, Hyung-Yil
    • Transactions of the Korean Society of Mechanical Engineers A
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    • v.36 no.2
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    • pp.125-135
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    • 2012
  • The FE model for shot peening often assume that shots impact vertically on the engineering parts to generate compressive residual stresses. However, the shots obliquely impact on the surface in actual peening. In this work, we propose a 3D finite element (FE) model for evaluation of residual stress under angled shot peening. Using the FE model for angled multi-impact, we examine the effects of factors such as impact angle, impact pattern and the number of shots. Plastic deformation of shot is also considered. To validate the model, we then compare the FE solution with experimental result by X-ray diffraction (XRD). The proposed model will be a base of 3D multi-impact FE model with diverse impact angles.

A 3D FEA Model with Plastic Shots for Evaluation of Peening Residual Stress due to Multi-Impacts (다중충돌 피닝잔류응력 평가를 위한 소성숏이 포함된 3차원 유한요소해석 모델)

  • Kim, Tae-Hyung;Lee, Hyungy-Il
    • Transactions of the Korean Society of Mechanical Engineers A
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    • v.32 no.8
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    • pp.642-653
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    • 2008
  • In this paper, we propose a 3-D finite element (FE) analysis model with combined physical behavior and kinematical impact factors for evaluation of residual stress in multi-impact shot peening. The FE model considers both physical behavior of material and characteristics of kinematical impact. The physical parameters include elastic-plastic FE modeling of shot ball, material damping coefficient, dynamic friction coefficient. The kinematical parameters include impact velocity and diameter of shot ball. Multi-impact FE model consists of 3-D symmetry-cell. We can describe a certain repeated area of peened specimen under equibiaxial residual stress by the cell. With the cell model, we investigate the FE peening coverage, dependency on the impact sequence, effect of repeated cycle. The proposed FE model provides converged and unique solution of surface stress, maximum compressive residual stress and deformation depth at four impact positions. Further, in contrast to the rigid and elastic shots, plastically deformable shot produces residual stresses closer to experimental solutions by X-ray diffraction. Consequently, it is confirmed that the FE model with peening factors and plastic shot is valid for multi-shot peening analyses.