Residual Stress Field Prediction in Shot Peened Mechanical Parts with Complex Geometries (original) (raw)
Related papers
2017
Even when properly controlled, shot peening treatment may induce a complex residual stresses (RS) field depending on the geometry of the treated part. Hence, among the variables which affect the fatigue behaviour of shot peened components, the geometry could play a major role. The more widespread method for predicting RS after shot peening consists in modelling the process by simulating the impacts between the shot and the treated part. When the geometry become complex, this method is not consistent with industrial constraints in terms of computing time. Thus the need is to develop a methodology in order to generate the RS field into a shot peened mechanical part with complex non flat geometries, and consequently predict the lifetime in a high cycle fatigue (HCF) regime.
Residual Stress Measurement on Shot Peened Samples Using FIB-DIC
Shot peening is an established technique for improving the fatigue resistance of mechanical components by performing a deformation treatment that causes local near surface plastic deformation and introduces a layer of compressive residual stress. The knowledge of the residual stress distribution plays a crucial role in the correct prediction of fatigue life during service in the context of engineering design. Reliable prediction of safe fatigue life requires knowing how the residual stress state obtained after shot peening depends on the sample geometry, e.g. the presence of notches, and how it evolves during cyclic loading. The Focused Ion Beam milling coupled with Digital Image Correlation (DIC) analysis of SEM images (the FIB-DIC method) has been shown to be an efficient technique for stress evaluation at the (sub)micron-scale. The residual stresses in the vicinity of shot-peened rounded notch tips in Al-7075-T651 samples were studied as a function of notch radii (ρ =2, 0.5, 0.15...
Effects of Residual Compressive Stresses in the Shot Peening Process
International journal of engineering research and technology, 2014
This work presents the favorable effects of residual compressive stresses during shot peening process by varying different parameters such as shot velocity, shot angle, shot diameters. The shot peening process is largely used for the surface treatment of metallic components with the aim of increasing surface toughness and extending fatigue life. A secondary consequence of the process is that the residual stress distribution developed within the material may induce distortion of the component. This effect may therefore be used constructively in the straightening and forming of thin flexible metallic structures. The various techniques available for modeling the effect of peening with finite elements are discussed. In particular, a method of simulating the effect of peening on large flexible panels is presented. Analyses are shown in which a novel loading is applied to finite element meshes in order to produce the desired residual stress distribution. Results from tests are compared to finite element analyses with DOE and preliminary results of large scale analyses are presented.
Finite element analysis of residual stress induced by shot peening process
Advances in Engineering Software, 2003
The aircraft industry has only recently begun to explore possible application of welding as an alternative joining method for the design of future large civil airliner wing. One of the main obstacles, encountered in the past years, to welding application within the aircraft industries were due to failure in the weldments, caused by high tensile residual stresses present in the region of the weld, reducing drastically fatigue strength of welded joints. Improvement in the fatigue life of the welded joint can be obtained if compressive residual stresses are introduced at the weld region.Shot peening is a manufacturing process intended to give aircraft structures the final shape and to introduce a compressive residual state of stress inside the material in order to increase fatigue life. This paper presents the modeling and simulation of the residual stress field resulting from the shot peening process. The results achieved show that a significant decrease of welding induced tensile residual stress magnitude can be obtained. Good agreement between experimental and numerical results was achieved.
Analytical modelling for residual stresses produced by shot peening
Materials & Design, 2009
In the present work, an analytical model for the residual stresses formed during the shot peening process is analysed. The model employed was proposed by Li and co-workers [Li J et al. Mechanical approach to the residual stress field induced by shot peening. Mater Sci Eng 1991;A147:167-73] and complemented by Shen and co-workers [Shen S et al. Assessment, development and validation of computational fracture mechanics methodologies and tools for shot-peened materials used in rotorcraft principal structural elements [S.I.], 2004]. However, two modifications are adopted: the hertzian pressure is considered as a dynamic load and the Ramberg-Osgood and/or Ludwick constitutive models of the stress-strain curve is adopted to describe the plastic behaviour of the target material. The resulting model is checked using experimental measurements obtained in the literature of residual stresses on a 4140 steel shot peened target as well as on our own data for shot peened Al 7475 alloy.
2005
This study was performed using the Finite Element Method with the main objective of simulating the shot peening process to evaluate the residual stresses. Shot peening was simulated considering the one single shot impact against a plate throughout an axisymmetric model. An integration explicit dynamic algorithm was employed, taking into consideration the elastic plastic behavior of the two bodies in contact. Slidelines were utilized to simulate the impact zone. The obtained results were compared with values of experimental expressions found in specialized literature. The finite element professional software denominated LUSAS(R) was used in the simulation.
Investigation of Residual Stresses after Shot Peening Processing
2019
Mechanical surface treatments using an elastic-plastic cold working process can develop residual stresses on the surface of a workpiece. Compressive residual stresses on the surface increase resistance against surface crack propagation, so the overall mechanical performance can be improved by this technique. Compressive residual stresses can be created by different methods such as hammering, rolling, and shot peening. Shot peening is a well-established method to induce compressive residual stresses in the metallic components using cold working, and often ascribed to being beneficial to fatigue life in the aerospace and automobile industries. In this method, the surface is bombarded by high-velocity spherical balls which cause plastic deformation of the substrate, leading to a residual compressive stress after shot peening on the surface of the part. Computational modeling is an appropriate and effective way which can predict the amount of produced residual stresses and plastic defor...
IJERT-Effects of Residual Compressive Stresses in the Shot Peening Process
International Journal of Engineering Research and Technology (IJERT), 2014
https://www.ijert.org/effects-of-residual-compressive-stresses-in-the-shot-peening-process https://www.ijert.org/research/effects-of-residual-compressive-stresses-in-the-shot-peening-process-IJERTV3IS060398.pdf This work presents the favorable effects of residual compressive stresses during shot peening process by varying different parameters such as shot velocity, shot angle, shot diameters. The shot peening process is largely used for the surface treatment of metallic components with the aim of increasing surface toughness and extending fatigue life. A secondary consequence of the process is that the residual stress distribution developed within the material may induce distortion of the component. This effect may therefore be used constructively in the straightening and forming of thin flexible metallic structures. The various techniques available for modeling the effect of peening with finite elements are discussed. In particular, a method of simulating the effect of peening on large flexible panels is presented. Analyses are shown in which a novel loading is applied to finite element meshes in order to produce the desired residual stress distribution. Results from tests are compared to finite element analyses with DOE and preliminary results of large scale analyses are presented.
Analytical Model to Predict Thermomechanical Relaxation of Shot Peening Induced Residual Stresses
Journal of Engineering for Gas Turbines and Power, 2010
Shot peening is widely used to improve the fatigue life of engine blades and rotors by inducing compressive residual stress on component surfaces. However, the residual stresses can relax due to exposure at high service temperature and mechanical loading. A physics-motivated analytical solution is developed to predict the residual stress relaxation at high temperature and under mechanical loading. In this thermomechanical relaxation model, the plastic strains in the shot peening layer and the substrate are obtained analytically by using linear kinematic hardening material law, and the plastic strain evolution at high temperature is modeled by using a recovery strain term. The final residual stress as a function of time, temperature, and mechanical loading is obtained analytically by combining this recovery strain with equilibrium and compatibility conditions. The whole method can be implemented into Microsoft Excel, and is easy to use and validate. As a special case, an analytical c...