Effect of welding residual stresses on local behavior of rectangular hollow section joints/Einfluss der Schweißeigenspannungen auf die Tragfähigkeit von Rechteck-Hohlprofil-KnotenTeil 1: Entwicklung eines numerischen Modells

Bauingenieur ◽  
2018 ◽  
Vol 93 (04) ◽  
pp. 152-159 ◽  
Author(s):  
M. Garifullin ◽  
B. Launert ◽  
M. Heinisuo ◽  
H. Pasternak ◽  
K. Mela ◽  
...  
Keyword(s):  
Residual Stresses ◽  
Structural Engineering ◽  
Experimental Studies ◽  
Welding Process ◽  
Element Model ◽  
Structural Behavior ◽  
Initial Stiffness ◽  
Hollow Section ◽  
Tubular Joints ◽  
Thermomechanical Simulation

Welded tubular joints are widely used in structural engineering due to their excellent resistance and stiffness in contrast to open sections, as well as simpler end preparation. Welding residual stresses that occur in these joints after the welding process can affect their structural behavior. Some recent experimental studies have shown that this effect can be considerable. This study numerically evaluates the influence of welding residual stresses on the behavior of rectangular hollow section T joints. The paper consists of two parts. Part I develops and validates a finite element model for the joints directly taking into account welding residual stresses by means of an upstream thermomechanical simulation of the welding process. It is proven that particular attention needs to be paid to the discretization of the model, the material properties and the adequate description of the weld heat input. The validation with experimental results shows that the developed numerical model properly captures the local structural behavior of tubular joints and can be efficiently used for further investigations. Part II employs the constructed model to investigate the effect of welding residual stresses on the resistance and initial stiffness of the considered joints.

Effect of welding residual stresses on local behavior of rectangular hollow section joints/Einfluss der Schweißeigenspannungen auf die Tragfähigkeit von Rechteck-Hohlprofil-KnotenTeil 2: Parameterstudien

Bauingenieur ◽  
2018 ◽  
Vol 93 (05) ◽  
pp. 207-213
Author(s):  
M. Garifullin ◽  
B. Launert ◽  
M. Heinisuo ◽  
H. Pasternak ◽  
K. Mela ◽  
...  
Keyword(s):  
Residual Stresses ◽  
Welding Process ◽  
Element Model ◽  
Positive Influence ◽  
Structural Behavior ◽  
Initial Stiffness ◽  
Hollow Section ◽  
Tubular Joints ◽  
Welding Sequence ◽  
Parametric Analyses

Welding residual stresses that occur in tubular joints after the welding process affect their structural behavior. To ensure that these stresses do not negatively act on the load-bearing capacity of joints, their influence should be carefully investigated. This paper represents the second part of a study that numerically evaluates the structural behavior of rectangular hollow section T joints taking into account welding residual stresses. The finite element model developed in Part 1 is now used to evaluate their effect on the resistance and initial stiffness of tubular joints. The conducted parametric analyses show that welding residual stresses have a positive influence of 1–19 % on the plastic resistance of tubular joints and insignificantly reduce their initial stiffness. At the same time, the behavior of the considered joints is found not to depend on the welding sequence.

Evaluation by FEM of the Influence of the Preheating and Post-Heating Treatments on Residual Stresses in Welding

2014 ◽  
Vol 627 ◽  
pp. 93-96 ◽  
Author(s):  
Raffaele Sepe ◽  
Enrico Armentani ◽  
Giuseppe Lamanna ◽  
Francesco Caputo
Keyword(s):  
Temperature Distribution ◽  
Residual Stresses ◽  
Gas Metal Arc Welding ◽  
Welding Process ◽  
Element Model ◽  
Butt Joint ◽  
Temperature Fields ◽  
Heating Process ◽  
Butt Weld ◽  
Metal Arc Welding

During the last few years various experimental destructive and non-destructive methods were developed to evaluate residual stresses. However it is impossible to obtain a full residual stress distribution in welded structures by means of experimental methods. This disadvantage can be solved by means of computational analysis which allows to determine the whole stress and strain fields in complex structures. In this paper the temperature distribution and residual stresses were determined in a single-pass butt joint welded by GMAW (Gas Metal Arc Welding) process by finite element model (FEM). A 3D finite parametric element model has been carried out to analyze temperature distribution in butt weld joints and thermo-mechanical analyses were performed to evaluate resulting residual stresses. Temperature fields have been investigated by varying an initial preheating treatment. Moreover the technique of “element birth and death” was adopted to simulate the process of filler metal addition The high stresses were evaluated, with particular regard to fusion zone and heat affected zone. The influence of preheating and post-heating treatment on residual stresses was investigated. The residual stresses decrease when preheating temperature increases. The maximum value of longitudinal residual stresses without pre-heating can be reduced about 12% and 38% by using the preheating and post-heating process respectively.

Numerical Simulation of Welding Induced Residual Stresses in a Circular Hollow Section T-Joint

2006 ◽  
Author(s):  
Suraj Joshi ◽  
Cumali Semetay ◽  
John W. H. Price ◽  
Herman Nied
Keyword(s):  
Residual Stresses ◽  
Cross Sections ◽  
Mining Industry ◽  
Welding Process ◽  
Civil Structures ◽  
Element Analysis ◽  
Hollow Section ◽  
3 Dimensional ◽  
Circular Hollow Section ◽  
Intense Heat

Heavily welded circular hollow cross sections (CHS) are a common feature in civil structures such as draglines used in the mining industry and other off-shore structures. The sheer mass of the weldment and the application of intense heat generated during the welding process give birth to significant residual stresses in the structure. Often, residual stresses are high enough to act to accelerate factors such as corrosion, crack growth and fatigue. The objective of this research investigation was to predict welding generated residual stresses in a typical CHS T-Joint using Sysweld+, a welding Finite Element Analysis software. The T-joint is the first of the four lacings welded on to the main chord of a BE 1370 mining dragline cluster (designated All) of a type which is often used in the mining industry in Australia. This work examines a massive 3-dimensional geometry, which is on a much larger scale than those examined in existing studies. The paper presents the results of the simulation of residual stresses generated during the welding process in a single weld pass and compares them with the approach used in the commonly used document R6-Revision 4, Assessment of the Integrity of Structures Containing Defects.

Residual Stresses in Butt Welding of Two Circular Pipes: An Experimental and Numerical Investigation

2014 ◽  
Author(s):  
Gurinder Singh Brar
Keyword(s):  
Finite Element Method ◽  
Residual Stress ◽  
Finite Element ◽  
Residual Stresses ◽  
Finite Element Model ◽  
Welding Process ◽  
Diffraction Method ◽  
Element Model ◽  
X Ray Diffraction ◽  
X Ray

Welding is a reliable and efficient joining process in which the coalescence of metals is achieved by fusion. Welding is carried out with a very complex thermal cycle which results in irreversible elastic-plastic deformation and residual stresses in and around fusion zone and heat affected zone (HAZ). A residual stress due to welding arises from the differential heating of the plates due to the weld heat source. Residual stresses may be an advantage or disadvantage in structural components depending on their nature and magnitude. The beneficial effect of these compressive stresses have been widely used in industry as these are believed to increase fatigue strength of the component and reduce stress corrosion cracking and brittle fracture. But due to the presence of residual stresses in and around the weld zone the strength and life of the component is also reduced. To understand the behavior of residual stresses, two 10 mm thick Fe410WC mild steel plates are butt welded using the Metal Active Gas (MAG) process. An experimental method (X-ray diffraction) and numerical analysis (finite element analysis) were then carried out to calculate the residual stress values in the welded plates. Three types of V-butt weld joint — two-pass, three-pass and four-pass were considered in this study. In multi-pass welding operation the residual stress pattern developed in the material changes with each weld pass. In X-ray diffraction method, the residual stresses were derived from the elastic strain measurements using a Young’s modulus value of 210 GPa and Poisson’s ratio of 0.3. Finite element method based, SolidWorks software was used to develop coupled thermal-mechanical three dimension finite element model. The finite element model was evaluated for the transient temperatures and residual stresses during welding. Also variations of the physical and mechanical properties of material with the temperature were taken into account. The numerical results for peak transverse residual stresses attained in the welded plates for two-pass, three-pass and four-pass welded joint were 67.7 N/mm2, 58.6 N/mm2, and 48.1 N/mm2 respectively. The peak temperature attained during welding process comes out to be 970°C for two-pass weld, 820.8°C for three-pass weld and 651.9°C for four-pass weld. It can be concluded that due to increase in the number of passes during welding process or deposition weld beads, the residual stresses and temperature distribution decrease. Also, the results obtained by finite element method agree well with those from experimental X-ray diffraction method.

Numerical Study of Welding Residual Stresses in Blisk Repairs by Patching

2020 ◽  
Author(s):  
Ricarda Berger ◽  
Benedikt Hofmeister ◽  
Cristian G. Gebhardt ◽  
Raimund Rolfes
Keyword(s):  
Residual Stresses ◽  
Numerical Study ◽  
Welding Process ◽  
Element Model ◽  
Parent Material ◽  
Heat Transfer Analysis ◽  
High Tech ◽  
Compressor Blades ◽  
Repair Procedure ◽  
Patch Repairs

Abstract Patching is a high-tech repair procedure that is very adequate for compressor blisks with larger damages. This repair concept has the advantage that the added patch provides the same mechanical strength as the parent material of the blade and the initial aerodynamic contour of the blade is fully restored. However, the welding process locally induces stresses in the heat affected zone at the patch-to-blisk interface. These welding residual stresses influence the fatigue life of the repaired blade and have to be considered during the design phase of patch repairs. In this work, we contribute to the design of patch repairs by introducing a numerical simulation to predict weld-induced stresses in repaired compressor blades. Therefore, a finite element model is developed that includes sequential thermal and mechanical analyses of blisk blades. The temperature field caused by the welding torch is determined by performing a transient heat transfer analysis. The model also reflects the changes in the geometry due to the additional patch material and subsequent re-contoured patch. Different patch geometries are evaluated and compared in terms of their resulting stress levels. Basically, two kinds of patch geometries with long and short welding seams are studied. The stationary stress distribution of the repaired blade results from the superposition of residual stresses with steady stresses due to rotational and pressure forces. Thus, we provide the basis for a new fatigue assessment of the repaired blade considering the residual stress level in the patch-to-blisk interface.

Analysis of Arc Welded Thin-Walled Cylinders to Investigate the Effects of Welding Process Parameters on Residual Stresses

2008 ◽  
Vol 575-578 ◽  
pp. 763-768
Author(s):  
Afzaal M. Malik ◽  
Ejaz M. Qureshi ◽  
Naeem Ullah Dar
Keyword(s):  
Residual Stresses ◽  
Process Parameters ◽  
Arc Welding ◽  
Research Work ◽  
Three Dimensional ◽  
Welding Process ◽  
Welding Current ◽  
Element Model ◽  
Welding Parameters ◽  
Thin Walled

The research work presents a computational methodology based on three-dimensional finite element model to simulate the gas tungsten arc welding (GTAW) of thin-walled cylinders. The aim was to study the effects of two basic welding parameters (welding speed and welding current) on weld induced residual stresses. The complex phenomenon of arc welding was numerically solved by sequentially coupled transient, non-linear thermo-mechanical analysis. The accuracy of the numerical model was validated through experiments for temperature distribution and residual stresses. The results reveals that the present simulation strategy can be used as a proper tool to get the optimized welding process parameters and minimize the in service failures of thinwalled structures due to residual stresses.

Numerical Modeling of AA2024-T3 Friction Stir Welding Process for Residual Stress Evaluation, Including Softening Effects

2014 ◽  
Vol 611-612 ◽  
pp. 1675-1682 ◽  
Author(s):  
Mads Rostgaard Sonne ◽  
Pierpaolo Carlone ◽  
Gaetano S. Palazzo ◽  
Jesper Henri Hattel
Keyword(s):  
Residual Stress ◽  
Residual Stresses ◽  
Welding Process ◽  
Element Model ◽  
Transverse Cross Section ◽  
Heat Transfer Analysis ◽  
Contour Method ◽  
Friction Stir ◽  
Longitudinal Residual Stress ◽  
Numerical Finite Element

In the present paper, a numerical finite element model of the precipitation hardenable AA2024-T3 aluminum alloy, consisting of a heat transfer analysis based on the Thermal Pseudo Mechanical model for heat generation, and a sequentially coupled quasi-static stress analysis is proposed. Metallurgical softening of the material is properly considered and included in the calculations by means of the Myhr and Grong model, implemented as a user subroutine in ABAQUS. Numerical outcomes are compared with experimental results, highlighting the intriguing predictive capabilities of the model for both temperatures and residual stresses. The contour method is employed to map the longitudinal residual stress distribution on a transverse cross section of the joint. The influence of the applied boundary conditions and of the release of the clamping system on residual stresses is also assessed.

A Numerical and Experimental Study of Distribution of the Residual Stress on the Shot Peened Low Alloy Steel

2018 ◽  
Vol 140 (4) ◽  
Author(s):  
Pham Quang Trung ◽  
David Lee Butler ◽  
Sridhar Idapalapati
Keyword(s):  
Residual Stresses ◽  
Shot Peening ◽  
Cold Working ◽  
Experimental Studies ◽  
Element Model ◽  
Working Process ◽  
Factors Affecting ◽  
Properties Of Materials ◽  
Compressive Residual Stresses ◽  
Good Agreement

Shot peening is a cold working process, which is used to enhance the properties of materials, especially the fatigue life as it induces large compressive residual stresses in the subsurface of materials. In this paper, the effect of the shot peening process on the topography of the shot peened surface and the distribution of the residual stresses in the subsurface of the material was systematically investigated. A technique to estimate the shot peening coverage was employed using a finite element model which was further developed using experimental results for increased accuracy. The comparison between the numerical and experimental studies gives a good agreement of the distribution of the residual stresses in the subsurface of the shot peened material. The shot peening pressure and media size are two main factors affecting on the presence of compressive residual stresses in the subsurface of the material.

Experimental studies on friction stir welding of aluminium alloy 5083 and prediction of temperature distribution using arbitrary Lagrangian–Eulerian-based finite element method

2021 ◽  
pp. 146442072110681
Author(s):  
R Pramod ◽  
Vikram Kumar S Jain ◽  
S Mohan Kumar ◽  
B Girinath ◽  
A Rajesh Kannan ◽  
...  
Keyword(s):  
Finite Element ◽  
Friction Stir Welding ◽  
Aluminium Alloy ◽  
Process Parameters ◽  
Experimental Studies ◽  
Welding Process ◽  
Element Model ◽  
Arbitrary Lagrangian Eulerian ◽  
Friction Stir ◽  
Friction Stir Welding Process

The present work focused on welding aluminium alloy 5083 using the friction stir welding process. Suitable welding process parameters were identified to fabricate a defect-free butt joint with a tool rotational speed of 1600 rpm, traverse speed of 20 mm/min and tilt angle of 3°. The microstructure at the nugget zone, thermo mechanically affected zone, heat-affected zone and base metal zone are examined. Mechanical properties of the weldment exhibited promising results with an average joint efficiency and hardness of 75.70% and 94.0 ± 5.0 vickers hardness, respectively. Fractography revealed ductile mode of failure in base and weld metal tensile samples. Furthermore, a 3D thermomechanical finite element model was utilized to simulate the friction stir welding process using the selected process parameters. Arbitrary Lagrangian–Eulerian-based model aided in predicting residual stress distributions and thermal history during the friction stir welding process.

Residual Stresses in TIG-Welded I-Beams. Experimental Test-Setup and Validation of Numerical Model

2007 ◽  
Vol 340-341 ◽  
pp. 1425-1430
Author(s):  
Maarten De Strycker ◽  
Peter Buffel ◽  
Jan Belis ◽  
Christof Fimmers ◽  
Wesley Vanlaere ◽  
...  
Keyword(s):  
Numerical Model ◽  
Residual Stresses ◽  
Welding Process ◽  
Element Model ◽  
Steel Beams ◽  
Fe Model ◽  
Stress Distributions ◽  
Determining Factor ◽  
Weld Seams ◽  
The Finite Element Model

The presence of residual stresses is a determining factor in the buckling behaviour of steel beams. It is therefore necessary to know the magnitude and the distribution of residual stresses in welded beams. Experimental measurements of these residual stresses are expensive, timeconsuming and they give no insight in the evolution of the stresses during the welding process. For these reasons it is interesting to have a numerical model which allows a prediction of the residual stresses due to welding and which allows a study of the parameters that have an influence on the residual stresses (e.g. yield stress, heat-input, thermal expansion coefficient, …). Such a numerical model can result in a proposal for a welding process that leads to less detrimental residual stress distributions in welded I-beams. However, the results of the numerical model must always be checked with reality. This contribution contains the experimental verification of the finite element model for both single plates and I-beams with rather small dimensions. First, an overview of generally accepted influencing factors on the residual stresses is given. After this introduction, a setup which allows control of the parameters for making reproducible weld seams is presented. This setup is usable for both plates and I-beams. Next it is described how the residual stresses in a plate and a beam were measured. Finally the results obtained from different configurations in the experiments are compared with the results from the FE-model. It is shown that the FE-model gives reliable predictions for the residual stresses.

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