Analysis of Temperature and Residual Stress Distribution in Laser Welding for Ta/Mo Lap Joints Using FEM

2013 ◽  
Vol 820 ◽  
pp. 220-224
Author(s):  
Liang Jin ◽  
Fang Fang Song ◽  
Guo Qiang Wei ◽  
Qi Guo
Keyword(s):  
Residual Stress ◽  
Stress Distribution ◽  
Laser Welding ◽  
Weld Zone ◽  
Welding Process ◽  
Physical And Mechanical Properties ◽  
Element Model ◽  
Lap Joints ◽  
Residual Stress Distribution ◽  
Laser Welding Process

A nonlinear transient three-dimensional finite element model for the laser welding process is developed to investigate the temperature and residual stress distribution. All the major physical phenomena associated to the laser welding process, including temperature dependent thermo-physical and mechanical properties are taken into account in the model. The heat input to the model is assumed to be a Gaussian heat source. Results show that the temperature distribution of laser welding is consistent with the actual, and along-welding line longitudinal stress and transverse stress are retained in the weld zone after laser welding and cooling to the room temperature.

scholarly journals Evolution Mechanism of Transient Strain and Residual Stress Distribution in Al 6061 Laser Welding

Crystals ◽  
2021 ◽  
Vol 11 (2) ◽  
pp. 205
Author(s):  
Youmin Rong ◽  
Yu Huang ◽  
Lu Wang
Keyword(s):  
Residual Stress ◽  
Stress Distribution ◽  
Laser Welding ◽  
Weld Zone ◽  
Residual Stress Distribution ◽  
Al 6061 ◽  
Starting Position ◽  
Transient Strain ◽  
Weld Profile ◽  
Tension State

Considering the harm that residual stress causes to the mechanical properties of a weld joint, the evolution mechanisms of transient strain and residual stress distribution are investigated in laser welding of Al 6061, considering that these originate from non-uniform temperature distribution and are intensified further by the unbalanced procedure of melting and solidification. Thermal-elastic-plastic finite element method is developed and analyzed, while the actual weld profile is novel fitted by a B-spline curve. Transient strain is extracted by strain gauges. Longitudinal strain starts from a fluctuating compressive state and progresses to an ultimate residual tension state at the starting and ending welding positions, respectively. The maximum fitting deviation of the weld profile is 0.13 mm. Experimental and simulation results of residual strain are 842.0 μ and 826.8 μ, with a relative error of 1.805% at the starting position and −17.986% at the ending position. Near the weld center, mechanical behavior is complexly influenced by thermal expansion and contraction in the weld zone and the reaction binding force of the solid metal. Within a distance between −10 mm and 10 mm, and longitudinal stress is in a tension state, transverse stress fluctuates with a high gradient (~100 MPa).

Numerical Simulation of Residual Stresses in a Spot Welded Joint

2003 ◽  
Vol 125 (2) ◽  
pp. 222-226 ◽  
Author(s):  
Xin Long ◽  
Sanjeev K. Khanna
Keyword(s):  
Residual Stress ◽  
Stress Distribution ◽  
Welded Joint ◽  
Physical And Mechanical Properties ◽  
Element Model ◽  
Residual Stress Distribution ◽  
Temperature Dependent ◽  
Welded Steel ◽  
Good Agreement ◽  
Spot Welded

An incremental and thermal-electro-mechanical coupled finite element model has been presented in this study for predicting residual stress distribution in a spot welded steel joint. Approximate temperature dependent material properties, including physical and mechanical properties, have been considered. The spot nugget shape and the residual stress distribution were obtained by simulation. The results obtained have been compared with experimental measurements, and good agreement is observed. The highest tensile residual stress occurs at the center of the nugget and the residual stress decreases towards the edge of the nugget.

Residual Stress Evaluation of Dissimilar Weld Joint Using Reactor Vessel Outlet Nozzle Mock-Up Model (Report-1)

2008 ◽  
Author(s):  
Itaru Muroya ◽  
Youichi Iwamoto ◽  
Naoki Ogawa ◽  
Kiminobu Hojo ◽  
Kazuo Ogawa
Keyword(s):  
Residual Stress ◽  
Stress Distribution ◽  
Welding Process ◽  
Reactor Vessel ◽  
Residual Stress Distribution ◽  
Test Model ◽  
Alloy 600 ◽  
Outlet Nozzle ◽  
Stress Evaluation ◽  
Weld Region

In recent years, the occurrence of primary water stress corrosion cracking (PWSCC) in Alloy 600 weld regions of PWR plants has increased. In order to evaluate the crack propagation of PWSCC, it is required to estimate stress distribution including residual stress and operational stress through the wall thickness of the Alloy 600 weld region. In a national project in Japan for the purpose of establishing residual stress evaluation method, two test models were produced based on a reactor vessel outlet nozzle of Japanese PWR plants. One (Test model A) was produced using the same welding process applied in Japanese PWR plants in order to measure residual stress distribution of the Alloy 132 weld region. The other (Test model B) was produced using the same fabrication process in Japanese PWR plants in order to measure stress distribution change of the Alloy 132 weld region during fabrication process such as a hydrostatic test, welding a main coolant pipe to the stainless steel safe end. For Test model A, residual stress distribution was obtained using FE analysis, and was compared with the measured stress distribution. By comparing results, it was confirmed that the FE analysis result was in good agreement with the measurement result. For mock up test model B, the stress distribution of selected fabrication processes were measured using the Deep Hole Drilling (DHD) method. From these measurement results, it was found that the stress distribution in thickness direction at the center of the Alloy 132 weld line was changed largely during welding process of the safe end to the main coolant pipe.

Experimental Analysis of Repair Welding Alternatives for Shipbuilding DH36 Plates

2020 ◽  
Vol 64 (04) ◽  
pp. 384-391
Author(s):  
Tetyana Gurova ◽  
Segen F. Estefen ◽  
Anatoli Leontiev ◽  
Plinio T. Barbosa ◽  
Valentin Zhukov ◽  
...  
Keyword(s):  
Residual Stress ◽  
Stress Distribution ◽  
Best Practice ◽  
Welding Process ◽  
Offshore Structures ◽  
Residual Stress Distribution ◽  
Shipbuilding Industry ◽  
Repair Welding ◽  
Ship Construction ◽  
Repair Techniques

Repair by welding is widely used in the shipbuilding industry during ship construction. The effect of the residual stress distribution induced by the welding process on the ship structure is important for the repair effectiveness. This article presents an experimental study of the residual stress distribution induced by repair welding in the plates that are typically used in ships and offshore structures. Different repair techniques are evaluated to identify the best practice associated with residual stress values. Recommendations for repair welding are discussed, and modifications to the present practice are proposed.

Residual stress distribution in built-in beams

2020 ◽  
pp. 146442072095861
Author(s):  
FA de Castro ◽  
Paulo P Kenedi ◽  
LL Vignoli ◽  
I I T Riagusoff
Keyword(s):  
Residual Stress ◽  
Finite Element ◽  
Stress Distribution ◽  
Cross Section ◽  
Cross Sections ◽  
Element Model ◽  
Residual Stress Distribution ◽  
Concentrated Load ◽  
Load Growth ◽  
Final Failure

Metallic hyperstatic structures, like beams, submitted to excessive loads, do not fail completely before fully yielding in more than one cross section. Indeed, for built-in beams, three cross sections must be fully yielded before the final failure can occur. So, modeling the evolution of the cross-section residual stress distribution is an important subject that should be addressed to guarantee the stress analysis modeling correctness. This paper analyses the residual stress distribution evolution, in critical cross sections, of built-in beams during a transversal concentrated load growth, until the final failure through hinges formation. A finite element model is also presented. The results show good matches with the numerical model, used as a reference.

Temperature Field and Residual Stress Analysis of the Gear on CO2 Laser Welding Process

2011 ◽  
Vol 86 ◽  
pp. 670-673
Author(s):  
Jian Luo ◽  
Fei Li ◽  
Ke Liang Xue ◽  
De Jia Liu ◽  
Hai Wei Zhang
Keyword(s):  
Residual Stress ◽  
Temperature Field ◽  
Laser Welding ◽  
Welding Process ◽  
Welding Residual Stress ◽  
Temperature Cycle ◽  
Residual Tensile Stress ◽  
Welding Seam ◽  
Welding Temperature ◽  
Laser Welding Process

The welding technique is one of important technologies on the gear manufacturing process. The special welding temperature cycle is the basic conditions of the welding residual stress appearance in the gear. The large welding residual stress will create the large deformation after the gear welding, which will affect the gear service behavior. In this paper, the finite element method has used to simulate the gear laser welding process. The temperature field and residual stress has described. The research results show that the biggest residual compressive stress appears on the transverse direction of welding region. In the longitudinal direction, the biggest residual tensile stress appears on both sides of the welding seam line. When the laser welding power is 2.4 kW and welding speed is 20mm/s, the no apparent welding deformation’s 20CrMnSi gear can be achieved really.

Comparison of Residual Stress Between MIG Welding and Friction Stir Welding

2012 ◽  
Vol 155-156 ◽  
pp. 1218-1222
Author(s):  
Lei Wang ◽  
Mitsuyosi Tsunori
Keyword(s):  
Residual Stress ◽  
Friction Stir Welding ◽  
Stress Distribution ◽  
Yield Strength ◽  
Room Temperature ◽  
Welding Process ◽  
Residual Stress Distribution ◽  
Mig Welding ◽  
Friction Stir ◽  
Friction Stir Welding Process

Residual stress distribution plays a very important role in welded structures, the aim of present work is to find out the effect of different welding methods on the residual stress distribution by means of neutron diffraction measurements and FE models simulation. 4 mm thick DH-36 steel plates were butt welded by MIG welding process and 5 mm thick AA 2024 aluminium alloy plates were butt welded by friction stir welding process. Results show that residual stresses of MIG welding process are higher than those of friction stir welding process. The peak residual stress of MIG weld is close to the room temperature uniaxial yield strength of DH-36 while the peak residual stress of friction stir weld is just about 50% of the room temperature uniaxial yield strength of AA2024. The size effect of MIG welded and effect of welding speeds of friction stir welded on the residual stress distribution have also been studied in the paper.

Effect of Welding Sequence on the Residual Stress Distribution in a Stiffened Plate

2016 ◽  
Author(s):  
Bai-Qiao Chen ◽  
C. Guedes Soares
Keyword(s):  
Residual Stress ◽  
Stress Distribution ◽  
Lower Layer ◽  
Plate Thickness ◽  
Three Dimensional ◽  
Welding Process ◽  
Residual Stress Distribution ◽  
Steel Plates ◽  
Tension Zone ◽  
Welding Sequence

This work investigates the temperature distribution, deformation and residual stress in steel plates as a result of different sequences of welding. The single-pass gas tungsten arc welding process is simulated by a three dimensional nonlinear thermo-elasto-plastic approach. It is observed that the distribution of residual stress varies through the direction of plate thickness. It is concluded that the welding sequence affects not only the welding deformation but also the residual stress mainly in the lower layer of the plates. An in-depth discussion on the pattern of residual stress distribution is presented, especially on the width of the tension zone. Smaller residual tension zone and slightly lower compressive stress are found in thicker plate.

Finite Element Analysis of Effects of Preheating and Postweld Heat Treatment on Residual Stress in Pipe Welding

2011 ◽  
Vol 314-316 ◽  
pp. 428-431 ◽  
Author(s):  
Hui Du ◽  
Dong Po Wang ◽  
Chun Xiu Liu ◽  
Hai Zhang
Keyword(s):  
Heat Treatment ◽  
Residual Stress ◽  
Finite Element ◽  
Stress Distribution ◽  
Welding Process ◽  
Postweld Heat Treatment ◽  
Element Model ◽  
Element Analysis ◽  
Pipe Welding ◽  
Postweld Heat

To simulate preheating and postweld heat treatment of Q345 steel pipe welding, the finite element model was established. The welding process was simulated by method of the ANSYS element birth and death technique. In this paper, to obtain the distribution of the temperature field and stress field in different situations, preheating processes with two different values of temperature and postweld heat treatment process were simulated respectively. The results show that preheating can homogenize residual stress distribution of the weldment and decrease the residual stress. The heat treatment reduces the residual stress in inner and outer walls by 24% and 70% respectively and the stress distribution is more even and stress concentration is reduced.

Effect of Friction on Residual Stress Distribution Induced by Split Sleeve Cold Expansion Process

2020 ◽  
Author(s):  
Mithun K. Dey ◽  
Dave Kim ◽  
Hua Tan
Keyword(s):  
Residual Stress ◽  
Finite Element ◽  
Stress Distribution ◽  
Compressive Residual Stress ◽  
Three Dimensional ◽  
Element Model ◽  
Residual Stress Distribution ◽  
Expansion Process ◽  
Cold Expansion ◽  
Three Dimensional Finite Element

Abstract Residual Stress distribution and parametric influence of friction are studied for the split sleeve cold expanded holes in Al 2024 T351 alloy, by developing a three-dimensional finite element model of the process. Fastener holes in the alloy are necessary for the manufacturing process, but they create a potential area for stress concentration, which eventually leads to fatigue under cyclic loading. Beneficial compressive residual stress distribution as a result of the split sleeve cold expansion process provides retardation against crack initiation and propagation at the critical zones near hole edges. In this parametric study, the influence of friction between contact surfaces of the split sleeve and mandrel is numerically investigated. Hole reaming process after split sleeve cold expansion is often not discussed. Without this post-processing procedure, split sleeve cold expansion is incomplete in practice, and its purpose of providing better fatigue performance is invalidated. This study presents results and an overview of the significance of friction with the consideration of the postprocessing of split sleeve cold expansion. The numerical results show that with increasing friction coefficient, compressive residual stress reduces significantly at the mandrel entry side, which makes the hole edge more vulnerable to fatigue. The different aspects of finite element modeling approaches are also discussed to present the accuracy of the prediction. Experimental residual stress observation or visual validation is expensive and time-consuming. So better numerical prediction with the transparency of the analysis design can provide critical information on the process.

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