Polycrystal Plasticity Modeling of Cyclic Residual Stress Relaxation in Shot Peened Martensitic Gear Steel

2010 ◽  
Vol 132 (3) ◽  
Author(s):  
Rajesh Prasannavenkatesan ◽  
David L. McDowell
Keyword(s):  
Residual Stress ◽  
Stress Relaxation ◽  
Residual Stresses ◽  
Shot Peening ◽  
Cyclic Plasticity ◽  
Residual Stress Field ◽  
Residual Stress Relaxation ◽  
Gear Steel ◽  
Polycrystal Plasticity ◽  
Compressive Residual Stresses

Using a three-dimensional crystal plasticity model for cyclic deformation of lath martensitic steel, a simplified scheme is adopted to simulate the effects of shot peening on inducing initial compressive residual stresses. The model is utilized to investigate the subsequent cyclic relaxation of compressive residual stresses in shot peened lath martensitic gear steel in the high cycle fatigue (HCF) regime. A strategy is identified to model both shot peening and cyclic loading processes for polycrystalline ensembles. The relaxation of residual stress field during cyclic bending is analyzed for strain ratios Rε=0 and −1 for multiple realizations of polycrystalline microstructure. Cyclic microplasticity in favorably oriented martensite grains is the primary driver for the relaxation of residual stresses in HCF. For the case of Rε=−1, the cyclic plasticity occurs throughout the microstructure (macroplasticity) during the first loading cycle, resulting in substantial relaxation of compressive residual stresses at the surface and certain subsurface depths. The initial magnitude of residual stress is observed to influence the degree (percentage) of relaxation. Describing the differential intergranular yielding is necessary to capture the experimentally observed residual stress relaxation trends.

Numerical Simulation of Residual Stresses Induced from Shot Peening with Finite Element Method

2013 ◽  
Vol 433-435 ◽  
pp. 1898-1901
Author(s):  
Li Juan Cao ◽  
Shou Ju Li ◽  
Zi Chang Shangguan
Keyword(s):  
Numerical Simulation ◽  
Finite Element Method ◽  
Residual Stress ◽  
Surface Layer ◽  
Residual Stresses ◽  
Shot Peening ◽  
Target Material ◽  
Residual Stress Field ◽  
State Of Stress ◽  
Compressive Residual Stresses

Shot peening is a manufacturing process intended to give components the final shape and to introduce a compressive residual state of stress inside the material in order to increase fatigue life. The modeling and simulation of the residual stress field resulting from the shot peening process are proposed. The behaviour of the peened target material is supposed to be elastic plastic with bilinear characteristics. The results demonstrated the surface layer affected by compressive residual stresses is very thin and the peak is located on the surface.

scholarly journals Small–Scale Experimental Investigation of Fatigue Performance Improvement of Ship Hatch Corner with Shot Peening Treatments by Considering Residual Stress Relaxation

2021 ◽  
Vol 9 (4) ◽  
pp. 419
Author(s):  
Jin Gan ◽  
Zi’ang Gao ◽  
Yiwen Wang ◽  
Zhou Wang ◽  
Weiguo Wu
Keyword(s):  
Residual Stress ◽  
Surface Roughness ◽  
Fatigue Life ◽  
Stress Relaxation ◽  
Stress Field ◽  
Shot Peening ◽  
Compressive Residual Stress ◽  
Fatigue Performance ◽  
Residual Stress Field ◽  
Residual Stress Relaxation

Ship hatch corner is a common structure in a ship and its fatigue problem has always been one of the focuses in ship engineering due to the long–term high–stress concentration state during the ship’s life. For investigating the fatigue life improvement of the ship hatch corner under different shot peening (SP) treatments, a series of fatigue tests, residual stress and surface topography measurements were conducted for SP specimens. Furthermore, the distributions of the surface residual stress are measured with varying numbers of cyclic loads, investigating the residual stress relaxation during cyclic loading. The results show that no matter which SP process parameters are used, the fatigue lives of the shot–peened ship hatch corner specimens are longer than those at unpeened specimens. The relaxation rate of the residual stress mainly depends on the maximum compressive residual stress (σRSmax) and the depth of the maximum compressive residual stress (δmax). The larger the values of σRSmax and δmax, the slower the relaxation rates of the residual stress field. The results imply that the effect of residual stress field and surface roughness should be considered comprehensively to improve the fatigue life of the ship hatch corner with SP treatment. The increase in peening intensity (PI) within a certain range can increase the depth of the compressive residual stress field (CRSF), so the fatigue performance of the ship hatch corner is improved. Once the PI exceeds a certain value, the surface damage caused by the increase in surface roughness will not be offset by the CRSF and the fatigue life cannot be improved optimally. This research provides an approach of fatigue performance enhancement for ship hatch corners in engineering application.

Surface Yield Strength Gradient versus Residual Stress Relaxation of 7075 Aluminum Alloy

2010 ◽  
Vol 160-162 ◽  
pp. 241-246 ◽  
Author(s):  
Yong Hui Hu ◽  
Yun Xin Wu ◽  
Guang Yu Wang ◽  
Jun Kang Guo
Keyword(s):  
Residual Stress ◽  
Aluminum Alloy ◽  
Stress Relaxation ◽  
Yield Strength ◽  
Residual Stresses ◽  
Shot Peening ◽  
Fatigue Property ◽  
7075 Aluminum Alloy ◽  
Residual Stress Relaxation ◽  
Stress Coefficient

Different distributed residual stresses were introduced by quenching and two shot-peening treatments on 7075 aluminum alloy. The residual stress distributions and micro-hardness profiles in surface layers were measured. Pre-stress coefficient characterizing contribution of local residual stresses to local yield strength is introduced to analyze residual stress relaxation under cyclic loading. Load testing shows that re-distribution of residual stresses and proportional decrease of the pre-stress coefficient would occur in the non-uniform structural residual stresses introduced by quenching, while great stress relaxation and non-linear decrease of the pre-stress coefficient would occur in the uniform surface residual stresses introduced by shot-peening. Additionally, advantages of surface compressive residual stress and micro yield strength on anti-fatigue property and on restraining initiation and propagation of surface micro cracks should be considered in the usually conservative engineering design.

Comparative study of the effective parameters on residual stress relaxation in welded aluminum plates under cyclic loading

2020 ◽  
Vol 21 (5) ◽  
pp. 505
Author(s):  
Yousef Ghaderi Dehkordi ◽  
Ali Pourkamali Anaraki ◽  
Amir Reza Shahani
Keyword(s):  
Residual Stress ◽  
Cyclic Loading ◽  
Stress Relaxation ◽  
Stress Amplitude ◽  
Cyclic Plasticity ◽  
Mean Stress ◽  
Effective Parameters ◽  
Perfect Plasticity ◽  
Residual Stress Relaxation ◽  
Aluminum Plates

The prediction of residual stress relaxation is essential to assess the safety of welded components. This paper aims to study the influence of various effective parameters on residual stress relaxation under cyclic loading. In this regard, a 3D finite element modeling is performed to determine the residual stress in welded aluminum plates. The accuracy of this analysis is verified through experiment. To study the plasticity effect on stress relaxation, two plasticity models are implemented: perfect plasticity and combined isotropic-kinematic hardening. Hence, cyclic plasticity characterization of the material is specified by low cycle fatigue tests. It is found that the perfect plasticity leads to greater stress relaxation. In order to propose an accurate model to compute the residual stress relaxation, the Taguchi L18 array with four 3-level factors and one 6-level is employed. Using statistical analysis, the order of factors based on their effect on stress relaxation is determined as mean stress, stress amplitude, initial residual stress, and number of cycles. In addition, the stress relaxation increases with an increase in mean stress and stress amplitude.

scholarly journals Prediction of Residual Stress Relaxation of Shot Peened 2024-T351 Aluminum Alloy: Part 1

2011 ◽  
Vol 462-463 ◽  
pp. 1355-1360
Author(s):  
Omar Suliman Zaroog ◽  
Aidy Ali ◽  
Sahari B. Barkawi
Keyword(s):  
Residual Stress ◽  
Stress Relaxation ◽  
Shot Peening ◽  
Applied Load ◽  
Cold Work ◽  
Cyclic Tests ◽  
Initial State ◽  
Loading Cycle ◽  
Residual Stress Relaxation ◽  
Alloy Part

It is important to account for residual stress relaxation phenomenon in the design of the component. Specimens of 2024-T351 aluminium alloy were used in this study. The specimens were shot peened under three different shot peening intensities. Cyclic tests for two load magnitudes were performed for 1, 2, 10, 1000 and 10000 cycles. Residual stresses, microhardness and the cold work percentage were measured at initial state and after each loading cycle for the three shot peening intensities and for the two loads. The study revealed that most of the drop in the residual stress, microhardness and cold work happened in the first cycle are dependent on the applied load.

Surface Modification Analysis after Shot Peening of AA 7075 in Different States

2013 ◽  
Vol 768-769 ◽  
pp. 519-525 ◽  
Author(s):  
Sebastjan Žagar ◽  
Janez Grum
Keyword(s):  
Residual Stress ◽  
Surface Layer ◽  
Residual Stresses ◽  
Aluminium Alloy ◽  
Shot Peening ◽  
Fatigue Testing ◽  
Stress Profile ◽  
Treatment Conditions ◽  
Stress Profiles ◽  
Compressive Residual Stresses

The paper deals with the effect of different shot peening (SP) treatment conditions on the ENAW 7075-T651 aluminium alloy. Suitable residual stress profile increases the applicability and life cycle of mechanical parts, treated by shot peening. The objective of the research was to establish the optimal parameters of the shot peening treatment of the aluminium alloy in different precipitation hardened states with regard to residual stress profiles in dynamic loading. Main deformations and main residual stresses were calculated on the basis of electrical resistance. The resulting residual stress profiles reveal that stresses throughout the thin surface layer of all shot peened specimens are of compressive nature. The differences can be observed in the depth of shot peening and the profile of compressive residual stresses. Under all treatment conditions, the obtained maximum value of compressive residual stress ranges between -200 MPa and -300 MPa at a depth between 250 μm and 300 μm. Comparison of different temperature-hardened aluminium alloys shows that changes in the Almen intensity values have greater effect than coverage in the depth and profile of compressive residual stresses. Positive stress ratio of R=0.1 was selected. Wöhler curves were determined in the areas of maximum bending loads between 30 - 65 % of material's tensile strength, measured at thinner cross-sections of individual specimens. The results of material fatigue testing differ from the level of shot peening on the surface layer.

Relaxation of Residual Stresses in Bearing Rings Based on the Optimal Geometric Setup of Equipment for Centerless Running

2019 ◽  
Vol 973 ◽  
pp. 183-188
Author(s):  
Albert V. Korolev ◽  
Andrei F. Balayev ◽  
Boris M. Iznairov
Keyword(s):  
Mathematical Model ◽  
Residual Stress ◽  
Stress Relaxation ◽  
Residual Stresses ◽  
Elastic Strain ◽  
New Approach ◽  
Technological Method ◽  
Residual Stress Relaxation ◽  
Bearing Rings

This paper discusses the technological method of residual stress relaxation of bearing rings by centerless running with cylindrical rolls. Described a new approach to relieve residual stresses by centerless running of elastically-deforming rolls on the basis of the geometrical setup of the equipment. It was found that geometrical setup of the equipment influences an elastic strain of parts and the degree of residual stress relaxation. We obtained a mathematical model for calculation of setup parameters to ensure the required variation value of elastic strain of the part. The results of experiments confirm the influence of the geometric setup on the magnitude of residual stress relaxation.

scholarly journals Micro-Hardness and Residual Stress Relaxation of 2024 T351 Aluminum Alloy

2011 ◽  
Vol 462-463 ◽  
pp. 343-348 ◽  
Author(s):  
Omar Suliman Zaroog ◽  
Aidy Ali ◽  
Sahari B. Barkawi ◽  
Rizal Zahari
Keyword(s):  
Residual Stress ◽  
Aluminum Alloy ◽  
Stress Relaxation ◽  
Shot Peening ◽  
X Ray Diffraction ◽  
Initial State ◽  
Load Amplitude ◽  
Initial Residual Stress ◽  
Residual Stress Relaxation ◽  
Two Stages

The residual stress relaxation can be divided into two stages: The first cycle relaxation and the following cycles. In both stages, residual stress relaxed considerably from the initial state. The aim of this study is to investigate the residual stress relaxation and microhardness reduction after first and second cyclic load. A 2024 T351 aluminum alloy specimens were shot peened into three shot peening intensities. The fatigue test for first and second cyclic loads of two loads 15.5 kN and 30 kN was performed. The initial residual stress and residual stress after the first and second cycle stress was measured for the three shot peening intensities using X-ray diffraction. Microhardness test was performed for each specimen. The results showed that the residual stress relaxation for first cycle was reached more than 40% of the initial residual stress and it depends on the load amplitude, and microhardness decreased for the first cycle reached 22% and also it depended on load amplitude.

Abrasive Waterjet Peening With Elastic Prestress: Subsurface Residual Stress Distribution

2007 ◽  
Author(s):  
Balaji Sadasivam ◽  
Alpay Hizal ◽  
Dwayne Arola
Keyword(s):  
Residual Stress ◽  
Stress Distribution ◽  
Stress Field ◽  
Yield Strength ◽  
Residual Stresses ◽  
Residual Stress Distribution ◽  
Abrasive Waterjet ◽  
Residual Stress Field ◽  
Surface Residual Stress ◽  
Compressive Residual Stresses

Recent advances in abrasive waterjet (AWJ) technology have resulted in new processes for surface treatment that are capable of introducing compressive residual stresses with simultaneous changes in the surface texture. While the surface residual stress resulting from AWJ peening has been examined, the subsurface residual stress field resulting from this process has not been evaluated. In the present investigation, the subsurface residual stress distribution resulting from AWJ peening of Ti6Al4V and ASTM A228 steel were studied. Treatments were conducted with the targets subjected to an elastic prestress ranging from 0 to 75% of the substrate yield strength. The surface residual stress ranged from 680 to 1487 MPa for Ti6Al4V and 720 to 1554 MPa for ASTM A228 steel; the depth ranged from 265 to 370 μm for Ti6Al4V and 550 to 680 μm for ASTM A228 steel. Results showed that elastic prestress may be used to increase the surface residual stress in AWJ peened components by up to 100%.

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