scholarly journals Thermal Analysis of Friction Stir Welding with a Complex Curved Welding Seam (TECHNICAL NOTE)

2019 ◽  
Vol 32 (10) ◽  
2018 ◽  
Vol 225 ◽  
pp. 01001 ◽  
Author(s):  
Bahman Meyghani ◽  
Mokhtar B Awang

Advanced welding of complex geometries promises significant development in the automotive industry. Friction Stir Welding (FSW) as a solid-state welding technique has spread quickly since its initial development by TWI in 1991. It has found applications in various industries, including railway, automotive, maritime and aerospace. Temperature during FSW plays a significant role, therefore thermal analysis of the process provides the opportunity to understand the process in detail, and also allows one to save energy and cost as well. However, experimental investigation of the thermal behaviour is challenging, because of inaccuracy in the measuring instruments. Thus, Finite Element Methods (FEMs) offer an appropriate approach for thermal modelling of the process. There is also a dilemma in defining the perpendicular movement of the tool on a curved surface. To clarify the problem, the tool needs to follow a regular pattern during curved movement, and it should have a perpendicular position to the surface at each point. However, previous literature modelled only a single point movement for the tool. Thus, the finite element package needs to be modified to develop a precise perpendicular movement for the tool. In this paper, a VDISP user defined subroutine is used to modify Abaqus® software for thermal analysis of a complex curved plate. The results of the paper show that the problem of the perpendicular movement of the tool is resolved and the thermal behaviour of the FSW is done with remarkable accuracy.


Author(s):  
P Jayaseelan ◽  
S Rajesh Ruban ◽  
M Suresh ◽  
NS Gowtham ◽  
P Saravanan

2011 ◽  
Vol 337 ◽  
pp. 507-510 ◽  
Author(s):  
Bin Lian Zou ◽  
Xin Qi Yang ◽  
Jia Hua Chen

In this work, a study of fatigue crack propagation (FCP) behavior of friction stir welding (FSW) joints of 7075-T6 aluminum alloy was carried out. Fatigue crack growth rate curves were determined for cracks growing in different locations of the welding lines, including prefabricated crack through welding seam center, advancing side (AS), retreating side (RS), and vertical to welding seam. A computational simulation of fatigue crack propagation was conducted by AFGROW with different stress ratios R, and the effects of R on FCP rate were analyzed. Results showed that the FCP rate in RS of the Heat Affected Zone (HAZ) was the lowest and the highest was in the region vertical to the welding seam. In the low stress intensity factor range (△K) region, the FCP rate in Nugget Zone (NZ) was lower than that in AS of the HAZ, but in the high △K region, the situation was contrary. Reasons of the results were analyzed. Compared with the standard of International Institute of Welding (IIW), FCP rates in all regions were lower and it concluded nice fatigue properties of FSW 7075-T6. The simulation made in terms of crack propagation rate (da/dN) versus △K generally showed a good agreement with the measured values. The study of effects of different R on FCP rates based on AFGROW indicated that FCP rates increased with increasing R.


Metals ◽  
2019 ◽  
Vol 9 (6) ◽  
pp. 621 ◽  
Author(s):  
Haitao Luo ◽  
Tingke Wu ◽  
Peng Wang ◽  
Fengqun Zhao ◽  
Haonan Wang ◽  
...  

Friction stir welding (FSW) material flow has an important influence on weld formation. The finite element model of the FSW process was established. The axial force and the spindle torque of the welding process were collected through experiments. The feasibility of the finite element model was verified by a data comparison. The temperature field of the welding process was analyzed hierarchically. It was found that the temperature on the advancing side is about 20 °C higher than that on the retreating side near the welding seam, but that the temperature difference between the two sides of the middle and lower layers was decreased. The particle tracking technique was used to study the material flow law in different areas of the weld seam. The results showed that part of the material inside the tool pin was squeezed to the bottom of the workpiece. The material on the upper surface tends to move downward under the influence of the shoulder extrusion, while the material on the lower part moves spirally upward under the influence of the tool pin. The material flow amount of the advancing side is higher than that of the retreating side. The law of material flow reveals the possible causes of the welding defects. It was found that the abnormal flow of materials at a low rotation speed and high welding speed is prone to holes and crack defects. The forming reasons and material flow differences in different regions are studied through the microstructure of the joint cross section. The feasibility of a finite element modeling and simulation analysis is further verified.


Author(s):  
Mohd Atif Wahid ◽  
Pankul Goel ◽  
Zahid Akhtar Khan ◽  
Krishna Mohan Agarwal ◽  
Etkaf Hasan Khan

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