Influence of the Welding Sequence on Residual Stresses in Laser Welded T-Joints of an Airframe Aluminium Alloy

2008 ◽  
Vol 571-572 ◽  
pp. 375-380 ◽  
Author(s):  
Winulf Machold ◽  
Peter Staron ◽  
Funda S. Bayraktar ◽  
Stefan Riekehr ◽  
Mustafa Koçak ◽  
...  
Keyword(s):  
Residual Stress ◽  
Residual Stresses ◽  
Welding Process ◽  
Base Plate ◽  
Stress Fields ◽  
Stress Concentrations ◽  
T Joints ◽  
Element Simulation ◽  
Welding Sequence ◽  
Welding Sequences

The effect of different welding sequences between a 4.5 mm thick AA 6156 T6 base plate and a 2 mm thick AA 6013 T6 clip – resembling a skin-clip joint of an airframe – using a 3.3 kW Nd:YAG laser is investigated. Under cyclic loading the breakdown of such T-joints happens at one end of the clip, which is due to local residual stress concentrations. Recent measurements indicated that tensile stresses could be lower at the run-in than at the run-out locations. For a deeper investigation of this effect sheets with different welding sequences were produced. One welding sequence was made with two starting points in the centre, and a second with starting points at the clip ends. Temperature measurements were made using thermocouples to verify the heat conditions for a finite element simulation of the welding process, which is used for predictions of the residual stress distribution. Actual values of the residual stress fields were determined by neutron diffraction. The influences of the welding sequence on the measured temperatures and the residual stresses are discussed.

Co-Design Research on the Welding Structure of the Metro Bogie

2013 ◽  
Vol 365-366 ◽  
pp. 261-267
Author(s):  
Zhi Ming Liu ◽  
Wei Gang Hu ◽  
Yue Chen
Keyword(s):  
Residual Stress ◽  
Design Research ◽  
Design Method ◽  
Welding Process ◽  
Bogie Frame ◽  
Detail Design ◽  
Element Simulation ◽  
Welding Sequence ◽  
Structure Strength ◽  
Local Detail

In order to study the influence of welding process and local detail design to the life of the metro bogie frame, this paper, in view of the tee joint, researched the superposition of residual stress and external load influence on the structure strength by the finite element simulation to establish mechanical structure and welding process co-design method. Based on the above research, the fatigue strength of the overlapping structure of welding frame socket plate and beam was improved, by the co-design of the groove angle and joint-welding sequence.

Numerical Simulation of Welding Sequence Effect on Temperature Distribution, Residual Stresses and Distortions of T-Joint Fillet Welds

2011 ◽  
Vol 264-265 ◽  
pp. 254-259 ◽  
Author(s):  
N. Syahroni ◽  
M.I.P. Hidayat
Keyword(s):  
Numerical Simulation ◽  
Temperature Distribution ◽  
Residual Stresses ◽  
Angular Distortion ◽  
Element Simulation ◽  
Welding Sequence ◽  
And Performance ◽  
Welding Sequences ◽  
Two Sides ◽  
Contrary Direction

Welding sequence is one important factor which affects the residual stresses and distortions produced during welding, thus determines the welding quality and performance. In this paper, 3D numerical simulation of temperature distribution, residual stresses and distortions of the T-joint fillet weld with respect to the variation of welding sequence is presented. The finite element simulation involved thermo-mechanical analyses. Four welding sequences (WS) considered are one direction welding (WS-1), contrary direction welding (WS-2), welding from centre of one side (WS-3) and welding from centres of two sides (WS-4). The simulation results revealed that peak temperature achieved in the welding was greatly affected by the welding sequence and residual stress and angular distortion produced cannot both hold in minimum for a WS. The smallest residual stresses and the smallest angular distortions are related respectively to WS-2 and WS-4. The distributions of temperature, longitudinal and transverse residual stresses as well as angular distortions were also presented.

Evaluation of through-thickness residual stresses and microstructure in SA516 Gr. 70 steel welds

2021 ◽  
pp. 095440542199012
Author(s):  
Pradeeptta Kumar Taraphdar ◽  
Manas Mohan Mahapatra ◽  
Arun Kumar Pradhan ◽  
Pavan Kumar Singh ◽  
Kamal Sharma ◽  
...  
Keyword(s):  
Residual Stress ◽  
Residual Stresses ◽  
Nuclear Power ◽  
Three Dimensional ◽  
Welding Process ◽  
Influential Factors ◽  
Stress Fields ◽  
Pressure Vessel Steel ◽  
Vessel Steel ◽  
Steel Welds

The critical working condition of nuclear power plant equipment necessitates meticulous determination of the welding process and parameters. In this work, some major influential factors of welding were investigated to observe their effects on the through-thickness residual stress distribution in multipass pressure vessel steel welds. In this regard, experiments were conducted to find the characteristics of residual stresses dispersed in SA516 Grade 70 steel welds of different groove geometries with distinct welding conditions. Three-dimensional finite element models of the weldments were developed considering a moving heat source with temperature-dependent material properties to simulate the welding thermal cycles and corresponding residual stress fields. Effects of weld groove geometry, number of weld passes, external constraints, and preheating on the through-thickness residual stress fields were studied. Additional attention was given to the evaluation of the heterogeneous microstructure and microhardness across the weld cross-section associated with their weld thermal history. Finally, the evolution of the through-thickness residual stresses attributed to subsequent weld passes was elaborated.

Computational Models for Resistance Spot Welding

2012 ◽  
Author(s):  
Pierluigi Mollicone ◽  
Martin Muscat ◽  
Matthew Said
Keyword(s):  
Residual Stress ◽  
Residual Stresses ◽  
Spot Welding ◽  
Large Scale ◽  
Computational Models ◽  
Computational Modelling ◽  
Welding Process ◽  
Stress Fields ◽  
Modelling Technique ◽  
Hole Drilling

Spot welding is a very important joining process for many industries. Structural integrity of a spot welded joint is however compromised by the formation of residual stress fields, which arise due to the thermal loadings imposed on the material during this welding process. Experimental investigation of these effects is possible but often costly, especially in complex and large-scale applications. Computational models, through the application of advanced Finite Element Analysis (FEA) techniques, are hence of interest for the prediction, analysis and assessment of these effects. The computational modelling required to assess these effects is however relatively complex due to the interaction of thermal and structural solution fields. It follows that many decisions must be taken with regards to the modelling technique to adopt in these scenarios. This work presents a modelling technique for the prediction of spot welding induced residual stresses, validated with experimental measurements for the temperature and residual stress fields. The simulations, carried out in ANSYS, are aimed at using a general-purpose solver to predict residual stresses whilst the validation is carried out through transient thermocouple measurements and residual stress measurements done using the hole drilling method. Comparison of experimental and FEA model results highlight which parts and assumptions of the computational model are to be considered valid and hence its boundary for use in industry.

Residual Stress Analysis of Laser Welded Aluminium T-Joints Using Neutron Diffraction

2006 ◽  
Vol 524-525 ◽  
pp. 419-424 ◽  
Author(s):  
Funda S. Bayraktar ◽  
Peter Staron ◽  
Mustafa Koçak ◽  
Andreas Schreyer
Keyword(s):  
Residual Stress ◽  
Neutron Diffraction ◽  
Residual Stresses ◽  
Short Distance ◽  
Weld Seam ◽  
Base Plate ◽  
Laser Source ◽  
T Joints ◽  
Weld Residual Stress ◽  
Risk Areas

In this study the distribution and magnitude of residual stresses in a T-joint of aerospace grade aluminium alloy weldment was determined using neutron diffraction. A 2 mm thick AA 6013 sheet (as clip) was laser beam welded to a 6 mm thick AA 6056 base plate (as skin) to resemble the “short distance” welded clip-skin joints of an airframe. The total length of the weld was 120 mm and it was welded using 3.3 kW Nd:YAG laser source and 12% Si containing wire from one side only. No post weld heat treatment was applied after the welding. Start (run-in) and end (run-out) locations of the T-joints are generally considered as high risk areas with respect to solidification cracking and crack initiations under external loadings. It is of interest to investigate the weld residual stress fields at these locations to develop optimum joint design. Therefore, strain measurements have been performed not only in the middle of the weld seam but also at the run-in and run-out locations of these short distance welds. Higher longitudinal tensile residual stresses are detected at the run-out locations than the run-in locations. The measurements in the clip showed that the clip has a longitudinal tensile stress peak away (about 8 mm) from the weld seam.

Application of the Modified Deep Hole Drilling Technique (iDHD) for Measuring Near Yield Non-Axisymmetric Residual Stresses

2009 ◽  
Author(s):  
Amir-Hossein Mahmoudi ◽  
David J. Smith ◽  
Chris E. Truman ◽  
Martyn J. Pavier
Keyword(s):  
Residual Stress ◽  
Residual Stresses ◽  
Stress Fields ◽  
Hole Drilling ◽  
Deep Hole ◽  
Axisymmetric Stress ◽  
Deep Hole Drilling ◽  
Element Simulation ◽  
Drilling Technique ◽  
Shrink Fit

The modified deep hole drilling technique (iDHD) has been developed to allow near yield residual stresses to be measured and has been validated for axisymmetric residual stress fields. In the present investigation, the application of the iDHD technique was extended to non-axisymmetric stress fields. First, a finite element simulation of the iDHD technique was carried out to demonstrate its effectiveness at measuring near yield residual stress. Experimental measurements were then carried out on shrink fit specimens to investigate the performance of the technique in practice. These shrink fit specimens were assembled in such a way that either axisymmetric or non-axisymmetric stress fields could be generated. The results indicated that the iDHD technique is capable of measuring non-axisymmetric residual stresses in presence of plasticity.

scholarly journals Residual stresses in thermite welded rails: significance of additional forging

2020 ◽  
Vol 64 (7) ◽  
pp. 1195-1212
Author(s):  
B. Lennart Josefson ◽  
R. Bisschop ◽  
M. Messaadi ◽  
J. Hantusch
Keyword(s):  
Residual Stress ◽  
Stress Field ◽  
Residual Stresses ◽  
Weld Metal ◽  
Welding Process ◽  
Surface Zone ◽  
Fe Model ◽  
Uneven Surface ◽  
Residual Stress Field ◽  
High Dynamic

Abstract The aluminothermic welding (ATW) process is the most commonly used welding process for welding rails (track) in the field. The large amount of weld metal added in the ATW process may result in a wide uneven surface zone on the rail head, which may, in rare cases, lead to irregularities in wear and plastic deformation due to high dynamic wheel-rail forces as wheels pass. The present paper studies the introduction of additional forging to the ATW process, intended to reduce the width of the zone affected by the heat input, while not creating a more detrimental residual stress field. Simulations using a novel thermo-mechanical FE model of the ATW process show that addition of a forging pressure leads to a somewhat smaller width of the zone affected by heat. This is also found in a metallurgical examination, showing that this zone (weld metal and heat-affected zone) is fully pearlitic. Only marginal differences are found in the residual stress field when additional forging is applied. In both cases, large tensile residual stresses are found in the rail web at the weld. Additional forging may increase the risk of hot cracking due to an increase in plastic strains within the welded area.

Study on Welding Deformation and Residual Stress of H-Section Beam Based on Finite Element Method

2017 ◽  
Vol 753 ◽  
pp. 305-309 ◽  
Author(s):  
Xu Lu
Keyword(s):  
Mechanical Properties ◽  
Residual Stress ◽  
Finite Element ◽  
Source Parameters ◽  
Welding Process ◽  
Steel Structure ◽  
Bottom Plate ◽  
Welding Deformation ◽  
Element Simulation ◽  
Main Components

The welding H-section beam has good mechanical properties with its superior structure. So they become the main components of steel structure and have been widely used. In this paper, the welded H-section beam is used as the research object. The finite element simulation model is established. The heat source parameters are determined. The deformation of the steel due to the welding process is studied. The results show that the bottom plate and the bottom plate inward bending is about 2.32mm cause by welding process. The residual stress can reach 400MPa.

Numerical Simulation for Residual Stress and Deformation of Surface Welding on Membrane Water-Wall

2014 ◽  
Vol 490-491 ◽  
pp. 594-599
Author(s):  
Fan Ling Meng ◽  
Ai Guo Liu
Keyword(s):  
Residual Stress ◽  
Great Influence ◽  
Residual Deformation ◽  
Welding Residual Stress ◽  
Finite Element Software ◽  
Welding Sequence ◽  
Surface Welding ◽  
Stress And Deformation ◽  
Welding Sequences ◽  
Residual Stress And Deformation

Automatic MIG was adopted to weld Inconel 625 alloy on 20 G Membrane Waterwall, which can improve the capacities of high temperature corrosion resistance and wear resistance. To study the influence of Membrane Waterwall surface welding sequences on residual stress and residual deformation, this paper utilized finite element software ABAQUS and segmented moving heat source model to simulate the sequence welding, balanced welding from the middle to sides, balanced welding from sides to the middle, balanced skip welding from middle to sides and balanced skip welding from sides to the middle and studied their residual stresses and deformations. The simulation results indicated that there was a great influence of welding sequences on the residual stress and deformation. The optimal welding sequence was balanced skip welding from middle to sides and balanced skip welding from sides to the middle, which could change the stress distribution, decrease the welding residual stress by 17%, realize the even deformation of the whole welding section and decrease the bending deformation by 50%.

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.

Sign in / Sign up

Export Citation Format

Share Document