scholarly journals The effect of laser stitch welding residual stress on the dynamic behaviour of thin steel structure

2019 ◽  
Vol 13 (4) ◽  
pp. 5780-5790
Author(s):  
M. A. S. Aziz Shah ◽  
M. A. Yunus ◽  
M. N. Abdul Rani ◽  
A. M. Saman ◽  
M. S. M. Sani ◽  
...  
Keyword(s):  
Residual Stress ◽  
Finite Element ◽  
Welding Process ◽  
Steel Structure ◽  
Welding Residual Stress ◽  
Mode Shapes ◽  
Finite Element Models ◽  
Welded Structures ◽  
Welded Structure ◽  
Thin Steel

Laser stitch welding is one of the most reliable and efficient permanent metal joining processes in the automotive industry, particularly in the manufacturing of a car body-in-white (BIW). It is widely known that this welding process induces the generation of residual stresses that can influence the dynamic behaviours of welded structures. In order to accurately predict the dynamic behaviours of these welded structures, it is important to experimentally understand the influence of residual stress. Therefore, this study addresses the finite element modelling method of thin steel welded structures with and without the influences of residual stress in order to identify its effect towards dynamic behaviours. The finite element models of thin steel welded structures are developed by employing the area contact model (ACM2) format element connector.  The accuracy of the finite element models is then compared in terms of natural frequencies and mode shapes with the experimental counterparts. The dynamic behaviours of the measured structure are obtained using an impact hammer with free-free boundary conditions. The results demonstrate the importance of considering the influence of laser stitch welding residual stress in predicting the dynamic behaviours of thin steel welded structure.    

scholarly journals Finite Element Modelling of Laser Stitch Welding Joints for Structural Dynamic Predictions

2019 ◽  
Vol 16 (2) ◽  
pp. 6556-6567
Author(s):  
M. A. S. Aziz Shah ◽  
M. A. Yunus ◽  
M. N. Abdul Rani ◽  
M. S. Mohd Zin ◽  
W. I. I. Wan Iskandar Mirza
Keyword(s):  
Residual Stress ◽  
Finite Element ◽  
Dynamic Behaviour ◽  
Welding Process ◽  
Shell Element ◽  
High Strength ◽  
Mode Shapes ◽  
Finite Element Models ◽  
Structural Dynamic ◽  
Welded Structure

Laser stitch welding is a joining technique that has been increasingly popular in automotive industries, such as in the manufacturing and assembling of the car’s body-in-white (BiW) due to its advantages over the resistance spot weld, such as low heat application and high strength weld. The dynamic behaviour of a laser stitch welded structure is relatively difficult to predict accurately due to local parameters being induced during the laser welding process, such as heat affected zone (HAZ) and residual stress in the welded structure. This paper presents the idea of modelling the laser stitch weld by investigating different types of element connectors that can be used to represent laser stitch weld, such as rigid body element (RBE2), shell element (CQUAD4), bar element (CBAR) and area contact model (ACM2) format of element connectors. The accuracy of finite element models of laser stitch welded joints is compared in terms of natural frequencies and mode shapes with the experiment counterparts. The dynamic behaviour of the measured structure is obtained by using an impact hammer with free-free boundary conditions. It is found that the accuracy of the finite element models of the laser stitch welded structure highly depends on the involvement of residual stress and the heat affected zones that are generated from the welding process.

Influence Analysis of Welding Residual Stress for Seismic Behavior to Side-Plate Reinforced Section

2012 ◽  
Vol 256-259 ◽  
pp. 2074-2078
Author(s):  
Yun Liu ◽  
Cheng Chao Mao ◽  
Yong Jie Song ◽  
Xue Jing Song
Keyword(s):  
Residual Stress ◽  
Finite Element ◽  
Seismic Behavior ◽  
Welding Process ◽  
Welding Residual Stress ◽  
Finite Element Models ◽  
Side Plate ◽  
Research Objects ◽  
Seismic Index ◽  
Element Method

Taking side-plate reinforced section as research objects, this paper establishes the models by Ansys non-linear finite element method and simulates welding process of with birth-death element method. Comparing the different seismic index among test specimen and finite element models that based on whether or not considering welding residual stress, based on which, this research draws a conclusion that the influence of welding residual stress for seismic behavior to side-plate reinforced section is not obvious.

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.

Effects of Mechanical Loading on Residual Stress and Fracture: Part I — Background to the BS 7910:2013 Rules

2014 ◽  
Author(s):  
Isabel Hadley ◽  
Simon Smith
Keyword(s):  
Residual Stress ◽  
Stress Relaxation ◽  
Mechanical Loading ◽  
Mechanical Load ◽  
Welding Residual Stress ◽  
Assessment Procedure ◽  
Welded Structures ◽  
Interaction Factor ◽  
Welded Structure ◽  
The Uk

Failure of welded structures due to the presence of flaws is typically driven by a mixture of applied and residual stresses, yet in most cases only the former are known accurately. In as-welded structures, a typical assumption is that the magnitude of welding residual stress is bounded by the room temperature yield strength of the parent material. The UK flaw assessment procedure BS 7910:2013 also assumes that mechanical loading (either as a result of proof testing or during the initial loading of an as-welded structure) will bring about a relaxation in residual stress. Conversely, the UK structural assessment code for nuclear structures, R6, contains a warning on the ‘limited validation’ of the BS 7910 approaches for stress relaxation and suggests that they should be used ‘with caution’. The aim of this study was therefore to review the basis of the BS 7910 clauses on stress relaxation with a view to harmonising the BS 7910 and R6 rules for cases in which the original welding residual stress distribution is not known. The residual stress relaxation clauses of BS 7910:2013 date back to the 1991 edition of PD 6493 and have not changed substantially since then. A considerable programme of work was carried out by TWI at the time to justify and validate the clause, but the full underlying details of the work have not hitherto been available in the public domain, and are described in a separate companion paper. The approach proposed in BS 7910 combines ‘global’ relaxation of residual stress (Qm) under high mechanical load with ‘local’ enhancement of crack tip driving force through the adoption of a simplified primary/secondary stress interaction factor, ρ.

Analysis on the Welding Thermal Field and Residual Stress of Thick Plate

2015 ◽  
Vol 1095 ◽  
pp. 693-697
Author(s):  
Jiu Hong Jiang ◽  
Qiang Wang ◽  
Wen Lv
Keyword(s):  
Residual Stress ◽  
Finite Element ◽  
Thick Plate ◽  
Thermal Field ◽  
Welding Process ◽  
Source Model ◽  
Simulation Software ◽  
Welding Residual Stress ◽  
Element Simulation ◽  
Thick Steel

A 60mm Q345 rigid thick plate with V groove welding connection was modeled in order to simulate the welding residual stress by finite element method. Both element birth and death technique and double ellipse heat source model were introduced to simulate the welding process. The welding thermal field and residual stress of thick steel plate were analyzed by finite element simulation software ANSYS.Then the thermal field and residual stress distribution were visually demonstrated. The result shows that the thermal field shaped like a spindle during welding period and the residual stress at the mid-section in lateral, longitudinal and thickness direction of the welding joint is lower than the stress at the surface of the welding connection.

scholarly journals Estimation formula for residual stress from the blind-hole drilling method

2018 ◽  
Vol 10 (8) ◽  
pp. 168781401878740 ◽  
Author(s):  
Chi-Liang Kung ◽  
Ah-Der Lin ◽  
Po-Wei Huang ◽  
Chao-Ming Hsu
Keyword(s):  
Residual Stress ◽  
Finite Element ◽  
Welding Process ◽  
Welding Residual Stress ◽  
Hole Drilling ◽  
Parameter Group ◽  
Blind Hole ◽  
Finite Element Software ◽  
Inconel 690 ◽  
Stress Components

In this study, the accuracy of blind-hole method on weld residual stress estimation is investigated. A modified parameter group has also proposed to improve the accuracy. The thermal-elastic-plastic finite element model is employed to build up the residual stress distribution and the blind-hole process. The MSC Marc finite element software package is used to simulate the welding process and the welding residual stress and strain distributions around the weld of two inconel 690 alloy plates filled with I-52 GTAW filler. Then the process of the traditional blind hole is simulated by employing the inactive elements. The data of the residual strain variations of strain gages located around the blind hole is introduced into the blind-hole method to estimate the original residual stress components at the hole center. The effects of drilling depth, drilling size, gage radius, gage position, and the distance on the accuracy of estimated residual stress have also been studied and discussed. Based on the residual stress components simulated from the welding process, a modified stress parameter group has also been proposed to improve the accuracy of blind-hole method. Numerical results indicate that the accuracy of estimated residual stress can be improved significantly by employing the proposed blind-hole parameters.

scholarly journals Finite Element Prediction of Residual Stress Distributions in a Multipass Welded Piping Branch Junction

2006 ◽  
Author(s):  
Wei Jiang ◽  
Kadda Yahiaoui
Keyword(s):  
Residual Stress ◽  
Finite Element ◽  
Residual Stresses ◽  
Welding Process ◽  
Pressure Vessels ◽  
Welding Residual Stress ◽  
Stress Distributions ◽  
Multipass Welding ◽  
Hexahedral Elements ◽  
Element Removal

Piping branch junctions and nozzle attachments to main pressure vessels are common engineering components used in the power, oil and gas, and shipbuilding industries amongst others. These components are usually fabricated by multipass welding. The latter process is known to induce residual stresses at the fabrication stage which can have severe adverse effects on the in-service behavior of such critical components. It is thus desirable if the distributions of residual stresses can be predicted well in advance of welding execution. This paper presents a comprehensive study of three dimensional residual stress distributions in a stainless steel tee branch junction during a multipass welding process. A full 3D thermo-mechanical finite element model has been developed for this purpose. A newly developed meshing technique has been used to model the complex intersection areas of the welded junction with all hexahedral elements. Element removal/reactivate technique has been employed to simulate the deposition of filler material. Material, geometry and boundary nonlinearities associated with welding were all taken into account. The analysis results are presented in the form of stress distributions circumferentially along the weldline on both run and branch pipes as well as at the run and branch cross sections. In general, this computational model is capable of predicting 3D through thickness welding residual stress, which can be valuable for structural integrity assessments of complex welded geometries.

Effects of Mechanical Loading on Residual Stress and Fracture: Part II — Validation of the BS 7910:2013 Rules

2014 ◽  
Author(s):  
Isabel Hadley ◽  
Simon Smith
Keyword(s):  
Residual Stress ◽  
Stress Relaxation ◽  
Stress Distribution ◽  
Mechanical Loading ◽  
Welding Residual Stress ◽  
Numerical Work ◽  
Welded Structures ◽  
Interaction Factor ◽  
Welded Structure ◽  
The Uk

Failure of welded structures due to the presence of flaws is typically driven by a mixture of applied and residual stresses, yet in most cases only the former are known accurately. In as-welded structures, a typical assumption is that the magnitude of welding residual stress is bounded by the room temperature yield strength of the parent material. The UK flaw assessment procedure BS 7910:2013 also assumes that mechanical loading (either as a result of proof testing or during the initial loading of an as-welded structure) will bring about a relaxation in residual stress. Conversely, the UK structural assessment code for nuclear structures, R6, contains a warning on the ‘limited validation’ of the BS 7910 approaches for stress relaxation and suggests that they should be used ‘with caution’. The aim of this study was therefore to review the basis of the BS 7910 clauses on stress relaxation with a view to harmonising the BS 7910 and R6 rules for cases in which the original welding residual stress distribution is not known. A companion paper describes the history of the residual stress relaxation clauses of BS 7910. A considerable programme of work was carried out in the late 1980s to justify and validate the clauses, using a range of experimental and numerical work. This included analysis of work carried out by the UK power industry and used in the validation of the R6 procedure. The full underlying details of the work have not hitherto been available in the public domain, although the principles were published in 1988. The approach proposed in BS 7910 combines ‘global’ relaxation of residual stress (Qm) under high mechanical load with ‘local’ enhancement of crack tip driving force through the adoption of a simplified primary/secondary stress interaction factor, ρ. This is different from the method adopted by R6, but appears to be equivalent to allowing negative values of ρ under conditions of high primary stress. A re-analysis of the original TWI work, using the current version of BS 7910, has shown nothing to contradict the approach, which represents a workable engineering solution to the problem of how to analyse residual stress effects in as-welded structures rapidly and reasonably realistically when the as-welded stress distribution is unknown.

Structure Optimization and Welding Residual Stress Analysis of Twin-Web Turbine Disc

2012 ◽  
Vol 622-623 ◽  
pp. 309-314 ◽  
Author(s):  
Xiu Li Shen ◽  
Shao Jing Dong
Keyword(s):  
Residual Stress ◽  
Weight Loss ◽  
Finite Element ◽  
Numerical Calculation ◽  
Stress Analysis ◽  
Welding Process ◽  
Structure Optimization ◽  
Welding Residual Stress ◽  
Turbine Disc ◽  
Residual Stress Analysis

This paper has proposed a new shape of the twin-web turbine disc. Based on a design optimization of the shape of the twin-web turbine disc by finite element numerical calculation, we analyzed welding types and carried out the simulation of the welding process and obtained the residual stress. Finally we got a 5.8% weight loss and summarized residual stress of the welding and proved the feasibility of the new shape.

A Study on Numerical Analysis and Residual Stress Evaluation of Welded Joint

2008 ◽  
Vol 575-578 ◽  
pp. 799-804
Author(s):  
Sun Chul Huh
Keyword(s):  
Residual Stress ◽  
Rapid Heating ◽  
Welding Process ◽  
Welding Residual Stress ◽  
Welding Distortion ◽  
Light Weight ◽  
Element Analysis ◽  
Welding Condition ◽  
Heating And Cooling ◽  
Welded Structure

The structures of existing wings had holes for light weight and plates and frames were fixed with rivets or screws, thus, there were difficulties and limits in light weight. Welding process generates distortion and residual stress in the welding due to rapid heating and cooling. Welding distortion and residual in the welded structure result in many troubles such as dimensional inaccuracies in assembling and safety problem during service. The accurate prediction of welding residual stress is thus very important to improve the quality of welding and find the way to reduce itself. In this study, an improvement was made in current joint methods through EB welding and laser welding for light weight of wings and welding strength was measured through strength test. In addition, finite element analysis was performed for welding process so as to induce optimum welding condition.

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