Prediction of Residual Stress Relaxation of Shot Peened 2024-T351 Aluminum Alloy: Part 2

The initial compressive residual stresses induced or inherent in a component will not remain stable during the life of the component, it relax and redistributed. In design of the component, it is important to consider the relaxation of residual stress phenomenon. In this study, equations to predict residual stress relaxation of 2024 T351 aluminium alloy specimens were proposed. The equations developed from the experimental data of 2024 T351 aluminium alloy specimens that were shot peened under three different shot peening intensities and undergoing cyclic tests for two load magnitudes for 1, 2, 10, 1000 and 10000 cycles. The residual stress, cold work and microhardness results were recorded after each cyclic load as well as the initial state. The presented model incorporates parameters including the degree of cold work, initial induced residual stress and the number of applied loading cycles.

Download Full-text

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

Key Engineering Materials ◽

10.4028/www.scientific.net/kem.462-463.1355 ◽

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.

Download Full-text

Reverse bending fatigue of shot peened 7075-T651 aluminium alloy: The role of residual stress relaxation

International Journal of Fatigue ◽

10.1016/j.ijfatigue.2008.11.017 ◽

2009 ◽

Vol 31 (8-9) ◽

pp. 1225-1236 ◽

Cited By ~ 93

Author(s):

M. Benedetti ◽

V. Fontanari ◽

P. Scardi ◽

C.L.A. Ricardo ◽

M. Bandini

Keyword(s):

Residual Stress ◽

Stress Relaxation ◽

Aluminium Alloy ◽

Bending Fatigue ◽

Residual Stress Relaxation

Download Full-text

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

Key Engineering Materials ◽

10.4028/www.scientific.net/kem.462-463.343 ◽

2011 ◽

Vol 462-463 ◽

pp. 343-348 ◽

Cited By ~ 2

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.

Download Full-text

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

Journal of Engineering Materials and Technology ◽

10.1115/1.4001594 ◽

2010 ◽

Vol 132 (3) ◽

Cited By ~ 9

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.

Download Full-text