Analysis on the Residual Stresses in the Aluminum Alloy Friction Stir Welded Joints

2011 ◽  
Vol 291-294 ◽  
pp. 958-963
Author(s):  
Li Jie Cao
Keyword(s):  
Residual Stress ◽  
Aluminum Alloy ◽  
Residual Stresses ◽  
Simulation Analysis ◽  
Engineering Application ◽  
Stress Fields ◽  
Weld Strength ◽  
Technological Parameters ◽  
Friction Stir ◽  
Wide Range

The residual stress fields can have strong influences on the integrity and performance of friction stir welded aluminum alloy structure, comprehensive insight into the residual stress distribution is the key to the Friction stir welding (FSW) engineering application for a wide range of materials and thicknesses improving the weld strength and fatigue life. In this paper, the current state of the residual stresses in the FSW aluminum alloy joints is reviewed, The focus is on recent advances of experimental research, the results of numerical simulation analysis, and the effects of the technological parameters(welding speed, rotational speed, shoulder geometry et al.) on residual stress fields was evaluated. In the end, The controlling technique of residual stresses from published literatures is summarized.

Study on the Residual Stresses Distribution in Thick Pre-Stretched Aluminum Plate

2018 ◽  
Vol 764 ◽  
pp. 49-57
Author(s):  
Hun Guo ◽  
Dun Wen Zuo ◽  
Fei Hong Yin ◽  
Ya Feng He ◽  
Ji Xu ◽  
...  
Keyword(s):  
Residual Stress ◽  
Aluminum Alloy ◽  
Quantitative Analysis ◽  
Residual Stresses ◽  
Thick Plate ◽  
Engineering Application ◽  
Machining Distortion ◽  
Stress Strain Relation ◽  
Measurement Results ◽  
Aluminum Plates

It is one of the difficult problems in the manufacture of the integrated aircraft part of Machining distortion caused by residual stress. According to the characteristics of aluminum alloy pre stretched thick plate, the modified removal method for measuring residual stress in thick pre-stretched aluminum plates is proposed and the stress-strain relation matrix is deduced by elasticity theory. Moreover, the residual stresses in the specimen of 7075T7351 plate is measured by the proposed method, and the results are finally analyzed and compared with the data obtained by other methods. The results indicate that the proposed method is effective in measuring the residual stress in thick pre-stretched aluminum alloy plates. The measurement results can be used for the quantitative analysis of aerospace parts machining distortion caused by residual stress, and it has higher value in engineering application.

scholarly journals Study on residual stresses caused by underwater friction stir welding: FE modeling and ultrasonic measurement

2018 ◽  
Vol 233 (1) ◽  
pp. 118-137
Author(s):  
Solaleh Salimi ◽  
Pouya Bahemmat ◽  
Mohammad Haghpanahi
Keyword(s):  
Residual Stress ◽  
Friction Stir Welding ◽  
Residual Stresses ◽  
Ultrasonic Method ◽  
Stress Fields ◽  
Optimum Process ◽  
Friction Stir ◽  
Mechanical Deformations ◽  
Underwater Friction Stir Welding ◽  
Precipitation Phenomena

Predicting residual stresses arising from the thermal and mechanical loading history during engineering processes including welding would be a viable tool to reach the optimum process parameters. In the present article, an elasto-thermo-visco-plastic model has been employed to estimate the residual stress caused by the underwater friction stir welding, which are resulted by large thermo-mechanical deformations on one hand and rapid cooling arising from the enormous non-uniform boiling heat convention of water on the other hand. Finally, the numerical results are compared with experimental data acquired by the ultrasonic method to evaluate the accuracy of the simulation process. Regarding the low temperature during underwater friction stir welding, the employed constitutive equations result in acceptable residual stress fields, while for in-air case, the amount of error increases significantly due to experience of high temperatures and intensification in hardening precipitation phenomena.

Influence of Deep Rolling Process Parameters on Surface Residual Stress of AA7075-T651 Aluminum Alloy Friction Stir Welded Joint

2018 ◽  
Vol 939 ◽  
pp. 23-30 ◽  
Author(s):  
Adirek Baisukhan ◽  
Wasawat Nakkiew
Keyword(s):  
Residual Stress ◽  
Aluminum Alloy ◽  
Residual Stresses ◽  
Compressive Residual Stress ◽  
Welded Joint ◽  
Rolling Process ◽  
Rolling Speed ◽  
Deep Rolling ◽  
Friction Stir ◽  
Rolling Pressure

Friction stir welding is most commonly used for joining aluminum alloy parts. After welding, residual stresses occurred in the welded joint caused by non-uniform cooling rate. Friction stir welding usually generates tensile residual stress inside the workpiece which affects the strength in addition to the fatigue life of materials. Compressive residual stress usually is beneficial and it can be introduced by mechanical surface treatment methods such as deep rolling, shot peening, laser shock peening, etc. In this research, deep rolling was used for inducing compressive residual stress on surface of friction stir welded joint. The residual stresses values were obtained from X-ray diffraction machine. Influence of three deep rolling process parameters: rolling pressure, rolling speed and rolling offset on surface residual stresses at the welded joint were investigated. Each factor had 2 levels (23 full factorial design). The statistical analysis result showed that the rolling pressure, rolling speed, rolling offset, interaction between rolling pressure and rolling speed, interaction between rolling speed and rolling offset were statistically significant factors, with the most compressive residual stress value approximately -391.6 MPa. The appropriated deep rolling process parameters on surface residual stress of AA7075-T651 aluminum alloy friction stir welded joint were 1) rolling pressure about 150 bar 2) rolling speed about 1,400 mm/min 3) rolling offset about 0.1 mm.

Numerical Analysis of Triaxial Residual Stresses in Quenched 316H Stainless Steel

2007 ◽  
Vol 553 ◽  
pp. 7-14 ◽  
Author(s):  
A. Andrade Campos ◽  
Filipe Teixeira Dias
Keyword(s):  
Residual Stress ◽  
Stainless Steel ◽  
Residual Stresses ◽  
Numerical Study ◽  
Equivalent Stress ◽  
Stress Fields ◽  
Process Conditions ◽  
Flow Rule ◽  
Wide Range ◽  
Cylinders And Spheres

Residual stress fields can cause creep damage in thermally aged components, even in the absence of working loads. In order to study this issue, the authors present a numerical study on the development of triaxial residual stresses in stainless steel specimens. A mechanical model dedicated to the analysis of heat treatment problems is described. The presented formulations are implemented incrementally with a non-linear constitutive model, adequate to the simulation of a wide range of thermal processes. The flow rule is a function of the equivalent stress and the deviatoric stress tensor, of the temperature field and of a set of internal state variables. The thermomechanical coupled problem is solved with a staggered approach. Spray water quenching was used to generate residual stress fields in solid cylinders and spheres made from 316H stainless steel. Finite element simulations were performed to find out how process conditions and specimen geometry influence the resulting residual stress distributions. The results show that compressive residual stresses are developed near the surfaces of the cylinders and spheres while tensile residual stresses occur near the centre. The level of residual stresses was found to be dependent on the heat transfer coefficient.

scholarly journals Effect of Shot Peening on Redistribution of Residual Stress Field in Friction Stir Welding of 2219 Aluminum Alloy

Materials ◽  
2020 ◽  
Vol 13 (14) ◽  
pp. 3169 ◽  
Author(s):  
Lin Nie ◽  
Yunxin Wu ◽  
Hai Gong ◽  
Dan Chen ◽  
Xudong Guo
Keyword(s):  
Residual Stress ◽  
Aluminum Alloy ◽  
Friction Stir Welding ◽  
Stress Field ◽  
Shot Peening ◽  
Welding Residual Stress ◽  
Stress Fields ◽  
Residual Stress Field ◽  
Friction Stir ◽  
2219 Aluminum Alloy

Welding is one of the essential stages in the manufacturing process of mechanical structures. Friction stir welding structure of aluminum alloy has been used as a primary supporting member in aerospace equipment. However, friction stir welding inevitably generates residual stress that promotes the initiation and propagation of cracks, threatening the performance of the welded structure. Shot peening can effectively change the distribution of residual stress and improve the fatigue properties of materials. In this paper, friction stir welding and shot peening are performed on 2219 aluminum alloy plates. The residual stress fields induced by friction stir welding and shot peening are measured by using the X-ray diffraction method and incremental center hole drilling method, and the distribution characteristics of residual stress fields are analyzed. The effect of the pellet diameters and pellet materials used in shot peening on the redistribution of welding residual stress field are investigated. The pellet diameter used in the experiment is in the range of 0.6–1.2 mm, and the pellet material includes glass, steel, and corundum. This study provides guidance for the application of shot peening in friction stir welding structure of 2219 aluminum alloy.

Analysis of circumferentially welded thin-walled cylinders to study the effects of tack weld orientations and joint root opening on residual stress fields

2009 ◽  
Vol 223 (5) ◽  
pp. 1037-1049 ◽  
Author(s):  
N U Dar ◽  
E M Qureshi ◽  
A M Malik ◽  
M M I Hammouda ◽  
R A Azeem
Keyword(s):  
Residual Stress ◽  
Residual Stresses ◽  
Arc Welding ◽  
Operating Conditions ◽  
Stress Fields ◽  
Welded Structures ◽  
Prime Concern ◽  
Thin Walled ◽  
Tack Weld ◽  
Welding Processes

In recent years, the demand for resilient welded structures with excellent in-service load-bearing capacity has been growing rapidly. The operating conditions (thermal and/or structural loads) are becoming more stringent, putting immense pressure on welding engineers to secure excellent quality welded structures. The local, non-uniform heating and subsequent cooling during the welding processes cause complex thermal stress—strain fields to develop, which finally leads to residual stresses, distortions, and their adverse consequences. Residual stresses are of prime concern to industries producing weld-integrated structures around the globe because of their obvious potential to cause dimensional instability in welded structures, and contribute to premature fracture/failure along with significant reduction in fatigue strength and in-service performance of welded structures. Arc welding with single or multiple weld runs is an appropriate and cost-effective joining method to produce high-strength structures in these industries. Multi-field interaction in arc welding makes it a complex manufacturing process. A number of geometric and process parameters contribute significant stress levels in arc-welded structures. In the present analysis, parametric studies have been conducted for the effects of a critical geometric parameter (i.e. tack weld) on the corresponding residual stress fields in circumferentially welded thin-walled cylinders. Tack weld offers considerable resistance to the shrinkage, and the orientation and size of tacks can altogether alter stress patterns within the weldments. Hence, a critical analysis for the effects of tack weld orientation is desirable.

Finite Element Simulation Analysis on Residual Stress Relief of 7075 Aluminum Alloy Ring

2021 ◽  
Vol 1032 ◽  
pp. 135-140
Author(s):  
Shao Feng Wu ◽  
Xiang Sheng Gao ◽  
Xian Rang Zhang ◽  
Han Jun Gao
Keyword(s):  
Residual Stress ◽  
Aluminum Alloy ◽  
Simulation Analysis ◽  
Material Model ◽  
Stress Relief ◽  
Isotropic Hardening ◽  
7075 Aluminum Alloy ◽  
Vibration Stress ◽  
Structural Parts ◽  
Creep Constitutive Model

Vibration stress relief (VSR) and thermal stress relief (TSR) are important method to eliminate the residual stress of structural parts. The thermal vibratory stress relief (TVSR) is a new method to decrease and homogenize the residual stress. Based on the stress relaxation tests and the equivalent vibration equation of modal analysis, the creep constitutive model and the bilinear isotropic hardening plasticity material model (BISO) are combined to establish the numerical simulation model of TVSR of 7075 aluminum alloy ring part. The simulation results show that four different initial blank residual stress levels are obtained after quenching process, and the residual stress elimination and homogenization effect of TSR and TVSR is better than that of VSR. TVSR has a better effect on both residual stress elimination and homogenization, and the residual stress relief rate can reach more than 20%.

Process - Property Correlation of Friction Stir Welding of Marine Grade Aluminium Alloy 5083 Using Finite Element Analysis

2021 ◽  
Vol 163 (A2) ◽  
Author(s):  
M Sahu ◽  
A Paul ◽  
S Ganguly
Keyword(s):  
Mechanical Properties ◽  
Residual Stress ◽  
Finite Element ◽  
Friction Stir Welding ◽  
Residual Stresses ◽  
Process Variables ◽  
Friction Stir ◽  
Stress Region ◽  
Longitudinal Residual Stress ◽  
Process Property

In this article, a 3D finite element based thermo-mechanical model for friction stir welding (FSW) of a marine-grade aluminium alloy 5083 is proposed. The model demonstrates the thermal evaluation and the distribution of residual stresses and strains under the variation of process variables. The temperature profile of the weld joint during the FSW process and the mechanical properties of the joints are also experimentally evaluated. The necessary calibration of the model for the correct implementation of the thermal loading, mechanical loading, and boundary conditions was performed using the experimental results. The model simulation and experimental results are analyses in view of the process-property correlation study. The residual stress was evaluated along, and across the weld, centreline referred as longitudinal and transverse residual stresses, respectively. The magnitude of longitudinal residual stress is noted 60-80% higher than that of the transverse direction. The longitudinal residual stress generated a tensile oval shaped stress region around the tool shoulder confined to a maximum distance of about 25mm from the axis of the tool along the weld line. It encompasses the weld-nugget to thermo-mechanically affected zone (TMAZ), while the parent metal region is mostly experiences the compressive residual stresses. However, the transverse residual stress region appears like wing shaped region spread out in both the advancing and retreating side of the weld and occupying approximately double the area as compared to the longitudinal residual stresses. Overall, the study revealed a corelation between the FSW process variables such as welding speed and the tool rotational speed with the residual stress and the mechanical properties of the joint.

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