FEM Prediction of Welding Residual Stresses and Temperature Fields in Butt and T-Welded Joints

2011 ◽  
Vol 418-420 ◽  
pp. 1486-1493
Author(s):  
Afsaneh Razavi ◽  
Fatemeh Hafezi ◽  
Hossein Farrahi
Keyword(s):  
Residual Stress ◽  
Residual Stresses ◽  
Welded Joints ◽  
Parametric Design ◽  
Weld Zone ◽  
Three Dimensional ◽  
Welding Process ◽  
Temperature Fields ◽  
Residual Stress Field ◽  
Welding Processes

Residual stresses resulted from localized non-uniform heating and subsequent cooling during welding processes enact an important role in the formation of cracks and welding distortions and have severe effect on performance of welded joints. The present research performs a three dimensional transient thermo Elasto-plastic analysis using finite element technique to simulate welding process. Welding simulation procedure is developed using the parametric design language of commercial code ANSYS for single pass T and butt welded joints. The procedure verified with predicted residual stress field found in literature to confirm the accuracy of the method. The material of the weld metal, HAZ and the base metal are assumed to be the same. With regards to high temperature gradient in weld zone, temperature dependant thermal and mechanical properties have been incorporated in the simulation. Also in this work the technique of element birth and death was employed to simulate moving heat source and the weld filler variation with time. Temperature and residual stress fields were discussed.

Analysis of Welded Joint Under Residual Stresses

2014 ◽  
Author(s):  
H. P. Jawale ◽  
Rahul Singh
Keyword(s):  
Residual Stress ◽  
Residual Stresses ◽  
Welded Joint ◽  
Weld Zone ◽  
Welding Process ◽  
Fatigue Behaviour ◽  
Hole Drilling ◽  
Building Structures ◽  
Residual Stress Field ◽  
Stress Relieving

Welded joint is most commonly used for building structures and machine components. Welding process involves heating followed by uneven cooling causing residual stress field. In conjunction with stresses due to external loads, in-service behaviour is affected due to residual stress in welded components. It induces defects, also alters crack initiation life, fatigue behaviour, breaking strength, corrosion resistance and increases the susceptibility of structure to failure by fracture. The residual stress is function of cooling rate and the size of weld. The role of residual stress associated with welding is therefore very important while designing mechanical parts. Conventional methods like heat treatment and shot-peening techniques becomes difficult to be applied for reduction of residual stress in general purpose applications. The work presented in this paper describes the measurement of residual stress using stress relieving method, based on hole-drilling technique. Subsequently, residual stresses are relived and measured using strain rosette near the weld zone. These strains value is converted in to stress value. Residual stress is quantified with respect to yield strength, making it possible to be considered for safe designing of weld components.

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.

Fast Three-Dimensional Finite Element Analysis of Weld Overlay Application on a Formed Feeder Elbow

2011 ◽  
Author(s):  
Francis H. Ku ◽  
Pete C. Riccardella
Keyword(s):  
Residual Stress ◽  
Finite Element Analysis ◽  
Finite Element ◽  
Residual Stresses ◽  
Nuclear Reactor ◽  
Three Dimensional ◽  
Fe Method ◽  
Element Analysis ◽  
Weld Overlay ◽  
Welding Processes

This paper presents a fast finite element analysis (FEA) model to efficiently predict the residual stresses in a feeder elbow in a CANDU nuclear reactor coolant system throughout the various stages of the manufacturing and welding processes, including elbow forming, Grayloc hub weld, and weld overlay application. The finite element (FE) method employs optimized FEA procedure along with three-dimensional (3-D) elastic-plastic technology and large deformation capability to predict the residual stresses due to the feeder forming and various welding processes. The results demonstrate that the fast FEA method captures the residual stress trends with acceptable accuracy and, hence, provides an efficient and practical tool for performing complicated parametric 3-D weld residual stress studies.

Estimation of Residual Stresses in Steel Welded Joints Using Three Dimensional Finite Element Analysis

2018 ◽  
Author(s):  
Shivdayal Patel ◽  
B. P. Patel ◽  
Suhail Ahmad
Keyword(s):  
Residual Stress ◽  
Finite Element Analysis ◽  
Finite Element ◽  
Residual Stresses ◽  
Boundary Conditions ◽  
Welding Speed ◽  
Welded Joints ◽  
Plate Thickness ◽  
Welding Process ◽  
Element Analysis

Welding is one of the most used joining methods in the ship industry. However, residual stresses are induced in the welded joints due to the rapid heating and cooling leading to inhomogenously distributed dimensional changes and non-uniform plastic and thermal strains. A number of factors, such as welding speed, boundary conditions, weld geometry, weld thickness, welding current/voltage, number of weld passes, pre-/post-heating etc, influence the residual stress distribution. The main aim of this work is to estimate the residual stresses in welded joints through finite element analysis and to investigate the effects of boundary conditions, welding speed and plate thickness on through the thickness/surface distributions of residual stresses. The welding process is simulated using 3D Finite element model in ABAQUS FE software in two steps: 1. Transient thermal analysis and 2. Quasi-static thermo-elasto-plastic analysis. The normal residual stresses along and across the weld in the weld tow region are found to be significant with nonlinear distribution. The residual stresses increase with the increase in the thickness of the plates being welded. The nature of the normal residual stress along the weld is found to be tensile-compressive-tensile and the nature of normal residual stress across the weld is found to be tensile along the thickness direction.

Influence of Initial and Welding Residual Stresses on Low Cycle Fatigue and Ratcheting Response Simulations of Elbows

2017 ◽  
Author(s):  
Nazrul Islam ◽  
Tasnim Hassan
Keyword(s):  
Residual Stress ◽  
Residual Stresses ◽  
Low Cycle Fatigue ◽  
Simulation Models ◽  
Cycle Fatigue ◽  
Residual Stress Field ◽  
Element Analysis ◽  
Girth Welding ◽  
Stress States ◽  
Welding Processes

Earlier studies [1] showed that the ANSYS software package customized with an advanced rate-independent constitutive model was unable to simulate some of the low-cycle fatigue responses of elbow components. Hence, simulations are performed to investigate the influence of manufacturing and welding residual stresses on elbow low-cycle fatigue responses. The sequentially coupled thermo-mechanical finite element analysis is performed to determine the initial residual stress states in elbows due to the elbow manufacturing processes and welding of elbows to straight pipes. Real-time girth-welding processes are taken into account to simulate the welding induced residual stress field. Incorporating these initial residual stresses in the computations, low-cycle fatigue and strain ratcheting responses are simulated by ANSYS. The simulation responses demonstrate that the influence of manufacturing and welding residual stresses in elbows on its low-cycle fatigue responses is negligible. Hence, the question remains what is missing in the simulation models that some of the elbow low-cycle fatigue responses cannot be simulated.

Examination of the Welding Processes when Welding of Steel in Protective Gas Atmosphere of Gases with the Application of Modeling and Numerical Simulation

2017 ◽  
Vol 737 ◽  
pp. 133-139
Author(s):  
Helena Kravarikova
Keyword(s):  
Numerical Simulation ◽  
Computational Models ◽  
Three Dimensional ◽  
Welding Process ◽  
Real System ◽  
Temperature Fields ◽  
Software Systems ◽  
Butt Weld ◽  
Protective Gas ◽  
Welding Processes

Modelling and numerical simulation of technological welding processes is the creative experimental method. Simulation replaces a real system computer model. To create the model can be applied to many experiments under predetermined conditions and analysis of the results. The results can be optimized and implemented to a real system. In a relatively short time, it is possible to solve complex processes occurring in the melting phase of the welding process, using the most advanced computer technology. Appropriately selected algorithm of model experiments can help study the course of temperature fields and formation of stresses and strains in solving the problems in the field of welding. The result of thermal and structural tasks of numerical simulation using FEM are the temperature fields, stress fields and strain generated in the process of welding and welded parts during cooling. Procedure of solving the tasks can be applied to any weld shape and any material of welded parts. The results published in the paper were obtained by solving the thermal and stress- strain tasks in the ANSYS program. Modelling and numerical simulation open possibilities for the three dimensional analysis of the phenomena studied. Based on the development of numerical methods and their application, it is possible to create computational models. Their implementation in software systems opens new possibilities for the area of numerical simulation of technological welding processes. The paper described simulation fillet and butt weld made of stainless steel 17242.

scholarly journals Shielded Metal Arc and Thermite Welding Effect to Residual Stress, Hardness and Crack of R54-Rail Weld Joint

2020 ◽  
Vol 55 (4) ◽  
Author(s):  
Yurianto ◽  
Gunawan Dwi Haryadi ◽  
Sri Nugroho ◽  
Sulardjaka ◽  
Susilo Adi Widayanto
Keyword(s):  
Residual Stress ◽  
Residual Stresses ◽  
Base Metal ◽  
Heat Affected Zone ◽  
Welded Joints ◽  
Arc Welding ◽  
Welding Process ◽  
Shielded Metal Arc Welding ◽  
Metal Arc Welding ◽  
Crack Susceptibility

The heating and cooling at the end of the welding process can cause residual stresses that are permanent and remain in the welded joint. This study aims to evaluate the magnitude and direction of residual stresses on the base metal and heat-affected zone of rail joints welded by the manual shielded metal arc and thermite welding. This research supports the feasibility of welding for rail. The material used in this study is the R-54 rail type, and the procedure used two rail samples of one meter long each, welded using manual shielded metal arc welding and thermite welding. The base metal and heat-affected zone of the welded joints were scanned with neutron ray diffraction. The scan produces a spectrum pattern and reveals the direction of the residual stress along with it. We found the strain value contained in both types of welded joints by looking at the microstrain values, which we obtained using the Bragg equation. The results show that the magnitude and direction of the residual stress produced by manual shielded metal arc welding and thermite welding are not the same. Thermite welding produces lower residual stress (lower crack susceptibility) than manual shielded metal arc welding. The melt's freezing starts from the edge to the center of the weld to create random residual stresses. The residual stress results of both the manual shielded metal arc welding and thermite welding are still below the yield strength of the base metal.

scholarly journals A Time Saving Method to Compute Multi-Pass Weld Residual Stresses

2013 ◽  
Author(s):  
Lionel Depradeux ◽  
Frédérique Rossillon
Keyword(s):  
Residual Stress ◽  
Stress Field ◽  
Residual Stresses ◽  
Welding Process ◽  
Geometrical Parameters ◽  
Residual Stress Field ◽  
Time Saving ◽  
3D Geometry ◽  
Girth Welds ◽  
Number Of Passes

In order to obtain the residual stress field resulting from the welding process, numerical simulations of multi-pass welding have demonstrated their efficiency and have become an interesting alternative to practical measurements. However, in the context of engineering studies, it remains a difficult task to compute residual stresses for a very high number of passes with reasonable computation times. In this paper, a time-saving method is proposed to simulate the welding process, ensuring an accurate reproduction of the residual stress field with drastically reduced computation times. The method consists in including in the simulation only the last deposited pass, or a reduced number of appropriately selected passes. For a given material and a given heat input, the choice of remaining passes depends on the geometrical parameters. The method is applied to various geometries of austenitic pipes girth welds, which have been widely studied in the literature and standards. The results, confronted to multipass simulations including all the passes, and to literature results, are very satisfactory. Quasi-identical residual stress fields are computed in both cases with computation times divided by a factor comprised between 7 up to 12. Further computations are in progress on other configurations than girth-weld pipes, and more complex 3D geometry like J weld of bottom head nozzles.

Comparison Between Shrinkage Strain and FEM Thermo-Mechanical Method for Estimation of Welding Induced Residual Stresses

2021 ◽  
Author(s):  
Sachin Bhardwaj ◽  
R. M. Chandima Ratnayake
Keyword(s):  
Residual Stress ◽  
Plastic Zone ◽  
Residual Stresses ◽  
Welded Joints ◽  
Structural Integrity ◽  
Welding Process ◽  
Shrinkage Strain ◽  
Computational Time ◽  
Transient Temperature ◽  
Strain Method

Abstract Residual stress estimation in structural integrity procedures plays an important role during the fitness-for-service (FFS) assessment of girth welds. Various FFS codes and standards, such as API 579 and BS 7910, recommend predetermined residual stress profiles based on finite element modeling (FEM) coupled with experimental results. Nonlinearity associated with non-uniform temperature gradients’ distribution during welding can develop residual stress up to the yield strength of the material, in weld shrinkage and plastic zones. Plastic zone size, shape, and locations are critically important in reducing or controlling final distortions, decreasing the residual stress according to length scale, and defining the optimum sequence of the welding process. However, in practice, estimation of finally developed residual stresses is used in structural integrity procedures for determining the FFS of welded joints. Various FEM models employed in its assessment require large computational time in solving the complex thermo-mechanical phenomenon involved in the welding process. Shrinkage strain models have been found to be fast and effective in determining final residual stresses, once the size, location and shape of the plastic zone can be predetermined. This manuscript demonstrates a comparison between the shrinkage strain method and the moving heat source method, based on transient temperature development as a function of time. The results (or findings) reveal a high compromise between FEM thermo mechanical model and shrinkage strain method in determining final residual stresses with later consuming less computational time. The findings provide significantly important feedback to welded joints’ structural integrity assurance practitioners.

Sequential Transient Numerical Simulation of Inertia Friction Welding Process

2008 ◽  
Author(s):  
Medhat Awad El-Hadek ◽  
Mohammad S. Davoud
Keyword(s):  
Temperature Distribution ◽  
Residual Stresses ◽  
Friction Welding ◽  
Welding Process ◽  
Transient Temperature ◽  
Inertia Friction Welding ◽  
Residual Stress Field ◽  
Element Analysis ◽  
Full Field ◽  
Welding Processes

Inertia friction welding processes often generate substantial residual stresses due to the heterogeneous temperature distribution during the welding process. The residual stresses which are the results of incompatible elastic and plastic deformations in weldment will alter the performance of welded structures. In this study, three-dimensional (3D) finite element analysis has been performed to analyze the coupled thermo-mechanical problem of inertia friction welding of a hollow cylinder. The analyses include the effect of conduction and convection heat transfer in conjunction with the angular velocity and the thrust pressure. The results include joint deformation and a full-field view of the residual stress field and the transient temperature distribution field in the weldment. The shape of deformation matches the experimental results reported in the literature. The residual stresses in the heat-affected zone have a high magnitude but comparatively are smaller than the yield strength of the material.

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