scholarly journals On the Influence of Welding Residual Stresses on the Dynamic Behavior of Structures

2008 ◽  
Vol 15 (3-4) ◽  
pp. 447-458 ◽  
Author(s):  
A.C. Bezerra ◽  
L.C. Vieira ◽  
D.A. Rade ◽  
A. Scotti
Keyword(s):  
Residual Stresses ◽  
Dynamic Behavior ◽  
Dynamic Characteristics ◽  
Thermal Loading ◽  
Welding Residual Stress ◽  
Temperature History ◽  
Transient Temperature ◽  
Geometric Distortions ◽  
Welding Processes ◽  
Stiffening Effect

It is widely known that welding processes induce the generation of residual stresses, which, through the so-named stress stiffening effect, can influence the static and dynamic behavior of the welded components. Thus, accounting for this influence becomes important for the understanding of experimental observations and accurate modeling of the dynamic behavior. In this study, the numerical and experimental characterization of the influence of welding residual stresses on the flexural dynamic characteristics of rectangular plates is addressed. It is suggested a general modeling methodology based on finite elements comprising three subsequent analyses, namely: a thermal analysis to compute the transient temperature history due to welding thermal loading; a structural analysis accounting for plastic strains to obtain the welding residual stress fields and geometric distortions, and a dynamic analysis to compute the dynamic characteristics taking into account the stress-stiffening effect and geometric distortions. The results demonstrate the importance of considering the influence of welding residual stresses in the prediction of the flexural dynamic behavior of plates and the feasibility and efficiency of the simplified modeling approach, which can readily be extended to more complex situations, for characterizing this influence.

Evolution of Temperature Distribution and Microstructure in Multipass Welded AISI 321 Stainless Steel Plates With Different Thicknesses

2015 ◽  
Vol 137 (6) ◽  
Author(s):  
Soheil Nakhodchi ◽  
Ali Shokuhfar ◽  
Saleh Akbari Iraj ◽  
Brian G. Thomas
Keyword(s):  
Stainless Steel ◽  
Temperature Distribution ◽  
Residual Stresses ◽  
Arc Welding ◽  
Welding Process ◽  
Steel Plates ◽  
Temperature History ◽  
Transient Temperature ◽  
Multipass Welding ◽  
Aisi 321

Prediction of temperature distribution, microstructure, and residual stresses generated during the welding process is crucial for the design and assessment of welded structures. In the multipass welding process of parts with different thicknesses, temperature distribution, microstructure, and residual stresses vary during each weld pass and from one part to another. This complicates the welding process and its analysis. In this paper, the evolution of temperature distribution and the microstructure generated during the multipass welding of AISI 321 stainless steel plates were studied numerically and experimentally. Experimental work involved designing and manufacturing benchmark specimens, performing the welding, measuring the transient temperature history, and finally observing and evaluating the microstructure. Benchmark specimens were made of corrosion-resistant AISI 321 stainless steel plates with different thicknesses of 6 mm and 10 mm. The welding process consisted of three welding passes of two shielded metal arc welding (SMAW) process and one gas tungsten arc welding (GTAW) process. Finite element (FE) models were developed using the DFLUX subroutine to model the moving heat source and two different approaches for thermal boundary conditions were evaluated using FILM subroutines. The DFLUX and FILM subroutines are presented for educational purposes, as well as a procedure for their verification.

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.

Effect of Misalignment and Weld Induced Residual Stresses on the Local Buckling Response of Pipelines

2011 ◽  
Vol 133 (4) ◽  
Author(s):  
Aiman Al-Showaiter ◽  
Farid Taheri ◽  
Shawn Kenny
Keyword(s):  
Residual Stress ◽  
Stress State ◽  
Residual Stresses ◽  
Oil And Gas ◽  
Local Buckling ◽  
Welding Residual Stress ◽  
Combined Stress ◽  
Residual Stress State ◽  
Girth Welding ◽  
Welding Processes

The aim of the present study is to develop numerical modeling procedures to simulate and study the effect of girth weld induced residual stresses and geometric imperfections on the behavior of conventional carbon steel oil and gas pipelines. The effect of welding residual stresses was obtained through computational simulations of the multipass girth weld process. The numerical procedures were calibrated using available pubic domain data on stainless steel. The methodology for conducting the welding simulation is presented. A parametric analysis was conducted using the finite element methods to evaluate the effects of welding residual stress due to girth welding processes, joint-to-joint misalignment associated with the girth weld, internal pressure, axial force, and diameter to wall thickness ratio on the local buckling response of pipelines. The pipeline moment-curvature response was examined to determine the influence of these parameters. For the parameters investigated, results from this study have demonstrated the significance of residual stress state due to welding processes and girth weld misalignment on the local buckling response of pipelines subjected to monotonic loading with combined stress state.

Prediction of Residual Stresses and Distortions in Welded Structures

1993 ◽  
Vol 115 (1) ◽  
pp. 52-57 ◽  
Author(s):  
B. L. Josefson
Keyword(s):  
Residual Stresses ◽  
Spot Welding ◽  
Thermal Design ◽  
Welding Residual Stress ◽  
Temperature History ◽  
Residual Stress Field ◽  
Butt Welding ◽  
Box Beams ◽  
Design Loads ◽  
Good Agreement

A good knowledge of the welding residual stress field and the corresponding distortion is needed when the interaction between manufacturing stresses and future (mechanical and/or thermal) design loads is studied, for example, with respect to possible crack initiation and growth in the HAZ, and also with respect to buckling. It is proposed here that a qualitatively good estimate of the welding residual stresses can be obtained by using FEM without following the temperature history during welding and cooling in detail. The procedure proposed is applied to two different problems: multi-pass butt welding of pipes, and spot welding of box beams. For the case of multi-pass butt welding of pipes, experimental results are available and a good agreement with these results is observed.

Residual Stresses in Strength Mismatched Welded Pipes

2017 ◽  
Author(s):  
Ali Mirzaee-Sisan ◽  
Junkan Wang
Keyword(s):  
Residual Stress ◽  
Residual Stresses ◽  
Thermal Stresses ◽  
Structural Integrity ◽  
Welding Residual Stress ◽  
Temperature Fields ◽  
Transient Temperature ◽  
Element Analysis ◽  
Girth Welds ◽  
Welded Pipe

It is commonly understood that residual stresses can have significant effects on structural integrity. The extent of such influence varies and is affected by material properties, manufacturing methods and thermal history. Welded components such as pipelines are subject to complex transient temperature fields and associated thermal stresses near the welded regions. These thermal stresses are often high in magnitude and could cause localized yielding around the deposited weld metal. Because of differential thermal expansion/contraction episodes, misfits are introduced into the welded regions which in turn generate residual stresses when the structure has cooled to ambient temperature. This paper is based on a recently completed Joint Industry Project (JIP) led by DNV GL. It briefly reviews published experimental and numerical studies on residual stresses and strength-mismatched girth welds in pipelines. Several Finite Element Analysis (FEA) models of a reeling simulation have been developed including mapping an initial axial residual stress (transverse to the weld) profile onto a seamless girth-welded pipe. The initial welding residual stress distribution used for mapping was measured along the circumference of the girth welds. The predicted residual stresses after reeling simulation was subsequently compared with experimental measurements.

Methodology for Numerical Welding Simulation Validation: The Dissimilar Metal Weld Case

2013 ◽  
Author(s):  
Ph. Gilles ◽  
S. Courtin ◽  
R. Vincent ◽  
M. Yescas ◽  
F. Gommez
Keyword(s):  
Residual Stress ◽  
Residual Stresses ◽  
Welding Residual Stress ◽  
Stress Fields ◽  
Design Stage ◽  
Connected Components ◽  
Actual State ◽  
Cycle Fatigue ◽  
Dissimilar Metal ◽  
Welding Processes

Welding processes induce residual stresses and distortion in the welded joint and the connected components. For manufacturing purpose distortion is the main issue and up to now the problem is handled by post weld corrective actions. Welding residual stress fields are not considered at the design stage in French codes and standards. However, it is well known that residual stresses are likely to increase the risks of fatigue or corrosion and may cause failure in brittle materials. Ferritic parts of large components are post-weld heat treated; allowing disregarding the influence of residuals stresses thanks to their relief. Preventive measures, including mitigation by fine polishing are undertaken in corrosion sensitive zones. The influence of residual stresses on fatigue is more complex to analyze: in low cycle fatigue, residual stresses should be relieved or redistributed after few cycles with plastic straining, and for high cycle fatigue, residual stress effects are accounted for through a mean stress offsett. When considered, residual stress fields are often represented in a very crude manner by a membrane distribution of the most influent stress component through the thickness of the structure. In a less rough way, several codes or fitness-for-purpose guidelines (API [1], British standards [2]) propose residual stress profiles relative to several weld configurations. Nevertheless for a given case, the given profiles may differ significantly for several reasons: the degree of conservatism, the number of covered cases, the embedded margins accounting for uncertainties. Some ill-posed benchmark problems have shown that numerical simulation of residual stresses may deliver very scattered results. AREVA has therefore developed a methodology to validate welding simulations. The scope is limited to fusion welding. The simulations are based on a Thermo-Metallurgical Mechanical model in which the welding energy is represented by an equivalent heat source. This paper presents the actual state of development of this methodology which will be illustrated through 4 examples of residual fields in Dissimilar Metal Welds. Residual stress measurements have been performed for each of the four mock-ups by different techniques. Based on this important experimental and numerical campaign some actions of improvement of the validation methodology are finally listed.

Numerical Simulation of Temperature Field and Residual Stress in Multi-Pass Welds in 2.25Cr-1Mo-0.25V Steel Plate and Comparison With Experimental Measurements

2017 ◽  
Author(s):  
Mu Qin ◽  
Guangxu Cheng ◽  
Zaoxiao Zhang ◽  
Qing Li ◽  
Jianxiao Zhang
Keyword(s):  
Residual Stress ◽  
Temperature Distribution ◽  
Stress Distribution ◽  
Residual Stresses ◽  
Pressure Vessels ◽  
Residual Stress Distribution ◽  
Bottom Surface ◽  
Transient Temperature ◽  
Transient Temperature Distribution ◽  
Welding Processes

The 2.25Cr-1Mo-0.25V steels are widely used in the petroleum chemical industry for the manufacturing of pressure vessels. The multi-pass welding is a critical type of fabrication in hydrogenation reactor. However, very complicated residual stresses could be generated during the multi-pass welding process. The presence of residual stresses could have significant influence on the performance of welded product. In the present work, the transient temperature distribution and residual stress distribution in welding of 2.25Cr-1Mo-0.25V steel are analyzed by using numerical method. An uncoupled thermal-mechanical two-dimensional (2-D) FEM is proposed under the ABAQUS environment. The transient temperature distribution and the residual stress distribution during the welding processes are determined through the finite element method. A group of experiments by using the blind-hole method have been conducted to validate the numerical results. The results of 2-D model agree well with the experiment. The result shows that the maximum welding stress generated at heat affected zone (HAZ) both at the top and bottom surface whether to transverse stress or longitudinal stress.

Boundary Condition Design to Heat a Moving Object at Uniform Transient Temperature Using Inverse Formulation

2004 ◽  
Vol 126 (3) ◽  
pp. 619-626 ◽  
Author(s):  
Hakan Ertu¨rk ◽  
Ofodike A. Ezekoye ◽  
John R. Howell
Keyword(s):  
Boundary Condition ◽  
Temperature Distribution ◽  
Design Problem ◽  
Manufacturing Industry ◽  
Three Dimensional ◽  
Chemical Deposition ◽  
Iterative Solution ◽  
Conveyor Belt ◽  
Temperature History ◽  
Transient Temperature

The boundary condition design of a three-dimensional furnace that heats an object moving along a conveyor belt of an assembly line is considered. A furnace of this type can be used by the manufacturing industry for applications such as industrial baking, curing of paint, annealing or manufacturing through chemical deposition. The object that is to be heated moves along the furnace as it is heated following a specified temperature history. The spatial temperature distribution on the object is kept isothermal through the whole process. The temperature distribution of the heaters of the furnace should be changed as the object moves so that the specified temperature history can be satisfied. The design problem is transient where a series of inverse problems are solved. The process furnace considered is in the shape of a rectangular tunnel where the heaters are located on the top and the design object moves along the bottom. The inverse design approach is used for the solution, which is advantageous over a traditional trial-and-error solution where an iterative solution is required for every position as the object moves. The inverse formulation of the design problem is ill-posed and involves a set of Fredholm equations of the first kind. The use of advanced solvers that are able to regularize the resulting system is essential. These include the conjugate gradient method, the truncated singular value decomposition or Tikhonov regularization, rather than an ordinary solver, like Gauss-Seidel or Gauss elimination.

Finite Element Analyses of Residual Stresses in Typical Welded Joints Used in Nuclear Power Plants and Comparisons With Experiments

2010 ◽  
Author(s):  
Dean Deng ◽  
Kazuo Ogawa ◽  
Nobuyoshi Yanagida ◽  
Koichi Saito
Keyword(s):  
Numerical Simulation ◽  
Residual Stress ◽  
Residual Stresses ◽  
Welded Joints ◽  
Nuclear Power ◽  
Power Plants ◽  
Butt Joint ◽  
Welding Residual Stress ◽  
Dissimilar Metal ◽  
Water Reactors

Recent discoveries of stress corrosion cracking (SCC) at nickel-based metals in pressurized water reactors (PWRs) and boiling water reactors (BWRs) have raised concerns about safety and integrity of plant components. It has been recognized that welding residual stress is an important factor causing the issue of SCC in a weldment. In this study, both numerical simulation technology and experimental method were employed to investigate the characteristics of welding residual stress distribution in several typical welded joints, which are used in nuclear power plants. These joints include a thick plate butt-welded Alloy 600 joint, a dissimilar metal J-groove set-in joint and a dissimilar metal girth-butt joint. First of all, numerical simulation technology was used to predict welding residual stresses in these three joints, and the influence of heat source model on welding residual stress was examined. Meanwhile, the influence of other thermal processes such as cladding, buttering and heat treatment on the final residual stresses in the dissimilar metal girth-butt joint was also clarified. Secondly, we also measured the residual stresses in three corresponding mock-ups. Finally, the comparisons of the simulation results and the measured data have shed light on how to effectively simulate welding residual stress in these typical joints.

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.

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