Investigation of Hydrostatic Pressure Effect on the Residual Stresses of Circumferentially Butt-Welded Steel Pipes

2012 ◽  
Vol 134 (3) ◽  
Author(s):  
M. Foroutan ◽  
M. E. Aalami-Aleagha ◽  
S. Feli ◽  
S. Nikabadi
Keyword(s):  
Structural Analysis ◽  
Residual Stresses ◽  
Internal Pressure ◽  
Transfer Problem ◽  
Three Dimensional ◽  
Welding Process ◽  
Heat Power ◽  
Welded Steel ◽  
Spherical Domain ◽  
Steel Pipes

In this paper, the effect of hydrostatic testing internal pressure on the residual stresses of circumferentially butt-welded steel pipes is investigated by a three dimensional finite elements simulation based on ansys11 code. Residual stresses due to welding process are calculated by an uncoupled analysis. In this analysis, at first, a transient heat transfer problem is solved. Output of this analysis is temperature distribution history .This output is used as the structural analysis load. Output of structural analysis is welding residual stresses. The most important part of such simulations is modeling of heat power source. In the present work, heat power of welding electrode is simulated by a moving heat source with Gaussian distribution on a spherical domain. The presented model is used for calculation of residual stresses in an 8 in. three pass butt-welded steel pipe. Finally, the effects of hydrostatic testing internal pressure on the residual stresses are studied by the proposed model. The results obtained from this study show that the hydrostatic testing pressure has a significant effect on residual stresses.

Investigation of Joint Groove Geometry Effect on the Residual Stresses in Circumferentially Butt-Welded Steel Pipes by the FEM Simulation

2011 ◽  
Vol 264-265 ◽  
pp. 229-234
Author(s):  
M. Foroutan ◽  
M.E. Aalami-Aleagha ◽  
S. Pirmoradi
Keyword(s):  
Residual Stresses ◽  
Fem Simulation ◽  
Welding Zone ◽  
Welded Steel ◽  
Spherical Domain ◽  
Steel Pipes ◽  
Transient Region ◽  
Joint Geometry ◽  
Element Simulation ◽  
Proposed Model

In this paper effect of joint groove geometry on the residual stresses in circumferentially butt-welded still pipes is investigated by the finite element simulation. The elements birth and death technique is used for modeling of filling metal and joint groove geometry. The electrode heat power is modeled by a moving heat source which has a Gaussian distribution on a spherical domain. By using a transient region, elements near the welding zone are refined in a good manner. For validation of the proposed model, results obtained from model are compared with experimental data. Then three different joint geometry; V-joint, U-joint and X-joint are studied by the presented model.

Minimization of Residual Stresses in Submerged Arc Welding Process of Oil and Gas Steel Pipes by Committee Machine

2014 ◽  
Vol 564 ◽  
pp. 519-524
Author(s):  
Seyed Jafar Golestaneh ◽  
N. Ismail ◽  
M.K.A.M. Ariffin ◽  
S.H. Tang ◽  
Mohammad Reza Forouzan ◽  
...  
Keyword(s):  
Residual Stresses ◽  
Arc Welding ◽  
Oil And Gas ◽  
Traditional Approach ◽  
Welding Process ◽  
Submerged Arc Welding ◽  
Committee Machine ◽  
Steel Pipes ◽  
Input Variables ◽  
Submerged Arc

Submerged arc welding (SAW) is a well-known method to weld seam in manufacturing of large diameters steel pipes in oil and gas industry. The main subject of SAW design is selection of the optimum combination of input variables for achieving the desired output variables of weld. Input variables include voltage, amperage and speed of welding and output variables include residual stresses due to welding. On the other hand, main target in multi response optimization (MRO) problem is to find input variables values to achieve to desired output variables. Current study is a combination and modification of some works of authors in MRO and SAW subjects. This study utilizes an experiment design according to Taguchi arrays. Also a committee machine (CM) modeling the problem by CM using two approaches. The first CM consists eight experts with traditional approach in computation and second CM includes elite experts. Genetic algorithm was applied to find CM weights and desired responses. Results show that proposed approach in CM has a smaller root mean squire error (RMSE) than traditional approach. The validation of CM model is done by comparison of results with simulation of SAW process and residual stresses in a finite element environment. Finally, the results show few differences between the real case responses and the proposed algorithm responses.

Study of the Effect of Boundary Conditions on Residual Stresses in Welding Using Element Birth and Element Movement Techniques

2003 ◽  
Vol 125 (4) ◽  
pp. 432-439 ◽  
Author(s):  
Ihab F. Z. Fanous ◽  
Maher Y. A. Younan ◽  
Abdalla S. Wifi
Keyword(s):  
Residual Stresses ◽  
Boundary Conditions ◽  
Three Dimensional ◽  
Welding Process ◽  
Computation Time ◽  
The Other ◽  
Two Dimensional ◽  
The Media ◽  
Three Dimensional Models ◽  
Element Movement

The structure in which the welding process is performed highly affects the residual stresses generated in the welding. This effect is simulated by choosing the appropriate boundary conditions in modeling the welding process. The major parameters of the boundary conditions are the method by which the base metal is being fixed and the amount of heat being applied through the torch. Other parameters may include the coefficients of thermal heat loss from the plate which may simulate the media in which the welding is taking place. In modeling the welding process, two-dimensional forms of approximation were developed in analyzing most of the models of such problem. Three-dimensional models analyzing the welding process were developed in limited applications due to its high computation time and cost. With the development of new finite element tools, namely the element movement technique developed by the authors, full three-dimensional analysis of the welding process is becoming in hand. In the present work, three different boundary conditions shall be modeled comparing their effect on the welding. These boundary conditions shall be applied to two models of the welding process: one using the element birth technique and the other using the element movement technique showing the similarity in their responses verifying the effectiveness of the latter being accomplished in a shorter time.

Measurement of Residual Stresses in a Type 316H Stainless Steel Offset Repair in a Pipe Girth Weld

2005 ◽  
Vol 128 (3) ◽  
pp. 420-426 ◽  
Author(s):  
S. Hossain ◽  
C. E. Truman ◽  
D. J. Smith ◽  
P. J. Bouchard
Keyword(s):  
Stainless Steel ◽  
Residual Stresses ◽  
Pipe Wall ◽  
Three Dimensional ◽  
Hole Drilling ◽  
Element Analysis ◽  
Steel Pipes ◽  
Stress Components ◽  
Dimensional Finite Element ◽  
Three Dimensional Finite Element

This paper presents measurements of the in-plane residual stress components through the wall of a 218mm long, 26mm deep repair weld, offset by 7mm from the centerline of a girth weld joining two type 316H stainless steel pipes approximately 37mm thick. The measurements were obtained using the deep hole drilling technique. Two locations were examined: (i) mid-length of the repair weld and (ii) the stop-end of the repair. Both measurements were taken along the girth weld centerline. The distributions and magnitudes of the measured longitudinal and transverse stress components at the two locations were very similar over the outer half of the pipe wall. Over the inner half of the pipe wall both components of stress were found to be significantly more compressive at the stop-end of the repair than at mid-length. In general, the transverse residual stresses were found to be lower than the longitudinal residual stresses at both locations. The measured stress profiles are compared with predicted residual stresses from a three-dimensional finite element analysis.

Welding Residual Stress of Flange-Plate Steel Reinforced Connections

2012 ◽  
Vol 446-449 ◽  
pp. 3495-3498
Author(s):  
Wei Wang ◽  
Chang Hao Zhang ◽  
Guan Feng Wang ◽  
Juan Zhang
Keyword(s):  
Residual Stresses ◽  
Three Dimensional ◽  
Welding Process ◽  
Welding Residual Stress ◽  
Welding Parameters ◽  
Heat Affect Zone ◽  
Moment Frame ◽  
Steel Moment Frame ◽  
Element Analysis ◽  
The Finite Element Analysis

The welding joint method is usually applied in the reinforcing process of the steel moment frame connections. The welding parameters are chosen and discussed and the finite element analysis is employed to analyze the completely penetration joint weld between the flange plates and the column flange. The three-dimensional thermo-structure simulation is conducted. Furthermore, the influence of the residual stresses on the the loading capacity of the reinforced connection is discussed. The temperature field during the welding process and the residual stresses distribution are given. The existence of the welding residual will highly increase the likelihood of brittle fracture of the steel in the heat affect zone.

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.

Comparison of Different Residual Stress Models of FSW Butt Joints for Thin Aluminum Alloy Plates

2012 ◽  
Vol 463-464 ◽  
pp. 642-646
Author(s):  
Xi Jing Wang ◽  
Na Li ◽  
Zhong Ke Zhang ◽  
Guo Jing Ruan
Keyword(s):  
Aluminum Alloy ◽  
Residual Stresses ◽  
Three Dimensional ◽  
Welding Process ◽  
Welding Distortion ◽  
Element Analysis ◽  
Elastic Plastic ◽  
Inherent Strain ◽  
Inherent Strain Method ◽  
Strain Method

At present, the main methods used to predict welding residual stresses are the three dimensional thermo-elastic-plastic FEA method and the inherent method.Many learners had simulated the residual stresses of FSW used the thermo -elastic-plastic FEA method which was proved to be time consuming and not very effective. The inherent strain method neglects the whole welding process, and predicts distortion using an elastic finite element analysis by applying the inherent strains on the structure. In this paper,the inherent strains are firstly obtained for an flat butt-joint of aluminum alloy through experiments and three dimensional thermo-elastic-plastic FEA. Computational and experimental results showed that the inherent strain method could predict welding distortion with acceptable accuracy and greatly reduced running time when comparing to the thermo-elastic-plastic FEA method.

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.

Finite Element Analysis of Residual Stresses in TT-Welded Joint of a Fixed Jacket Platform

2006 ◽  
Author(s):  
Kh. Rostami ◽  
A. R. M. Gharabaghi ◽  
M. R. Chenaghlou ◽  
A. Arablouei
Keyword(s):  
Finite Element ◽  
Residual Stresses ◽  
Thermal Stresses ◽  
Welded Joint ◽  
Welding Process ◽  
Element Analysis ◽  
Welded Steel ◽  
Buckling Strength ◽  
Structural Distortions ◽  
Weld Toe

Welded steel tubular joints are the kind of connections used extensively in the construction of fixed jacket platforms. The welding process creates considerable tensile residual stresses near the toe of TT-joint due to the rapid cooling and contraction of final welding layers. Welding produces thermal stresses that cause structural distortions, which influence the buckling strength of the structure. In this study thermal elasto-plastic analysis is carried out using ANSYS finite element techniques to evaluate the thermo-mechanical behavior and the residual stresses of the TT-joint. Moreover, the technique of element birth and death is employed to simulate the weld filler variation with time in TT-joint. The results show the considerable tensile residual stress near the weld toe that it may cause crack initiation in this region and threats the fatigue life of joint.

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