The Effect of Modelling Simplifications on the Prediction of Residual Stresses in a Multi-Pass Plate Groove Weld

2007 ◽  
Author(s):  
A. P. Warren ◽  
S. K. Bate ◽  
P. Hurrell
Keyword(s):  
Finite Element ◽  
Heat Source ◽  
Residual Stresses ◽  
Finite Element Analyses ◽  
Computational Power ◽  
Test Pieces ◽  
Single Bead ◽  
Welding Processes

The inherent complexity of modelling welding processes and the lack of computational power available to analysts have resulted in simplified methods being commonly utilised when predicting residual stresses in welded components. Despite considerable advances in computational power, it is still often not possible to run detailed 3D analyses of complex welded geometries within practical timescales. Against this background, a programme of work has been undertaken in order to investigate the effect these simplifications will have on the prediction of residual stresses on a number of test-pieces. The geometry investigated in this paper is a plate containing a “V” groove, which runs the length of the plate and is filled with eight mechanised TIG weld passes. This paper presents the results of a number of finite element analyses conducted of this geometry. The analyses presented have been conducted using the commercial finite element packages SYSWELD and ABAQUS, using a number of modelling simplifications. These simplifications include modelling the plate in 2D and the use of the bead lumping technique to idealise a number of beads as a single bead. Also considered are various methods of heat source representation, namely; a moving ellipsoidal heat source, prescribed temperature and block dumping. These analyses are compared and qualitative conclusions are drawn.

The Effect of Phase Transformations on Predicted Values of Residual Stresses in Welded Ferritic Components

2006 ◽  
Vol 524-525 ◽  
pp. 827-832 ◽  
Author(s):  
Alex P. Warren ◽  
Steve K. Bate ◽  
Richard Charles ◽  
C.T. Watson
Keyword(s):  
Finite Element ◽  
Residual Stresses ◽  
Phase Transformations ◽  
Welding Process ◽  
Heating And Cooling ◽  
Test Pieces ◽  
Property Data ◽  
Finite Element Package ◽  
Predicted Values ◽  
Welding Processes

The accurate prediction of the residual stresses present in welded structures can be of great importance to the fracture assessment of such components. Therefore, a large amount of benefit can be gained from improving techniques for measuring and numerically analysing these stresses. In recent years many advances have been made in the field of analysing residual stresses using finite element methods. That said, very little work has been conducted on the accurate modelling of welded ferritic components. This is largely due to the added complication of phase transformations that occur during the heating and cooling of such steels. The objective of the work presented in this paper was to improve understanding of the effect that phase transformations have on residual stresses present within welded ferritic structures. This was conducted by simulating such welding processes using the finite element package SYSWELD. An investigation was conducted to determine how phase transformations, and therefore residual stresses, are affected by the welding process used. Phase transformation and material property data available within SYSWELD were used for this analysis. An autogenously welded beam provided a simple basis for this qualitative investigation. In the future the manufacture and measurement of suitable test-pieces will enable these simulations to be validated.

The Effect of Modelling Simplifications on the Prediction of Residual Stresses in Thin-Walled Pipe Butt Welds

2006 ◽  
Author(s):  
A. P. Warren ◽  
S. K. Bate ◽  
R. Charles ◽  
D. M. O’Gara ◽  
P. M. Wood ◽  
...  
Keyword(s):  
Residual Stress ◽  
Finite Element ◽  
Residual Stresses ◽  
Computational Power ◽  
Butt Weld ◽  
Butt Welds ◽  
Thin Walled Pipe ◽  
Thin Walled ◽  
Predicted Values ◽  
Welding Processes

The inherent complexity of modelling welding processes and the lack of computational power available to analysts has resulted in simplified methods being commonly utilised when predicting residual stresses. Despite considerable advances in computational power, it is still often not possible to run detailed 3D analyses of complex welded geometries within practical timescales. Against this background, a programme of work has been undertaken to develop a weld modelling procedure which can be followed by analysts. This procedure will account for how various modelling simplifications affect the predicted values of residual stress. One common geometry, which it is often necessary to analyse using modelling simplifications is that of a thin-walled pipe butt weld. Typically this geometry is simulated using a 2D axisymmetric analysis. Despite the popularity of this modelling simplification the effects of its use are not fully understood. In order to feed into this procedure, work has therefore been conducted to better understand the effects modelling simplifications will have on the residual stress levels that are predicted when simulating multi-pass pipe butt welds. The geometry considered in this study is the thin walled austenitic pipe butt weld specimen originally studied in VORSAC 5th Framework European Union project. This paper presents the results of a number of finite element analyses conducted of this geometry. These analyses have been conducted using a combination of the finite element codes SYSWELD and ABAQUS. The aim of this study was to understand the effect that the use of 2D axisymmetric analyses, and other modelling simplifications, namely block dumping and bead lumping will have on the predicted values of residual stress.

scholarly journals Prediction of Residual Stresses in a Multipass Pipe Weld by a Novel 3D Finite Element Approach

2018 ◽  
Author(s):  
Hui Huang ◽  
Jian Chen ◽  
Blair Carlson ◽  
Hui-Ping Wang ◽  
Paul Crooker ◽  
...  
Keyword(s):  
Finite Element ◽  
Residual Stresses ◽  
High Performance ◽  
Large Scale ◽  
Graphics Processing Unit ◽  
Computational Cost ◽  
Three Dimensional ◽  
Processing Unit ◽  
Girth Welds ◽  
Welding Processes

Due to enormous computation cost, current residual stress simulation of multipass girth welds are mostly performed using two-dimensional (2D) axisymmetric models. The 2D model can only provide limited estimation on the residual stresses by assuming its axisymmetric distribution. In this study, a highly efficient thermal-mechanical finite element code for three dimensional (3D) model has been developed based on high performance Graphics Processing Unit (GPU) computers. Our code is further accelerated by considering the unique physics associated with welding processes that are characterized by steep temperature gradient and a moving arc heat source. It is capable of modeling large-scale welding problems that cannot be easily handled by the existing commercial simulation tools. To demonstrate the accuracy and efficiency, our code was compared with a commercial software by simulating a 3D multi-pass girth weld model with over 1 million elements. Our code achieved comparable solution accuracy with respect to the commercial one but with over 100 times saving on computational cost. Moreover, the three-dimensional analysis demonstrated more realistic stress distribution that is not axisymmetric in hoop direction.

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 Stress Intensity Factors due To Welding Residual Stresses for Circumferentially Cracked Pipes

2012 ◽  
Author(s):  
Chang-Young Oh ◽  
Ji-Soo Kim ◽  
Yun-Jae Kim ◽  
Young-Jin Oh ◽  
Kyoungsoo Lee ◽  
...  
Keyword(s):  
Finite Element ◽  
Stress Intensity ◽  
Residual Stresses ◽  
Stress Intensity Factors ◽  
Finite Element Analyses ◽  
Intensity Factors ◽  
Crack Face ◽  
Simple Method ◽  
Weld Geometry ◽  
Nonlinear Stress

This paper proposes a simple method to estimate stress intensity factors due to welding residual stresses. In this study, finite element analyses for circumferentially cracked pipe are performed to calculate stress intensity factors. Four cracked geometries and two types of weld geometry are considered. KI-solutions for the nonlinear stress distribution on the crack face were determined in accordance with codes and standards. The results are compared with KI-solutions from finite element results. It is found that proposed simple method agrees well with FE results.

Evaluation of Residual Stresses in Small Diameter Stainless Steel Pipe Welds by Two-Dimensional and Three-Dimensional Finite Element Analyses

2014 ◽  
Author(s):  
Francis H. Ku ◽  
Trevor G. Hicks ◽  
William R. Mabe ◽  
Jason R. Miller
Keyword(s):  
Residual Stress ◽  
Finite Element ◽  
Stainless Steel ◽  
Residual Stresses ◽  
Three Dimensional ◽  
Steel Pipe ◽  
3D Analysis ◽  
Two Dimensional ◽  
Finite Element Analyses ◽  
Stainless Steel Pipe

Two-dimensional (2D) and three-dimensional (3D) weld-induced residual stress finite element analyses have been performed for 2-inch Schedule 80 Type-304 stainless steel pipe sections joined by a multi-layer segmented-bead pipe weld. The analyses investigate the similarities and differences between the two modeling approaches in terms of residual stresses and axial shrinkage induced by the pipe weld. The 2D analyses are of axisymmetric behavior and evaluate two different pipe end constraints, namely fixed-fixed and fixed-free, while the 3D analysis approximates the non-axisymmetric segmented welding expected in production, with fixed-free pipe end constraints. Based on the results presented, the following conclusions can be drawn. The welding temperature contour results between the 2D and 3D analyses are very similar. Only the 3D analysis is capable of simulating the non-axisymmetric behavior of the segmented welding technique. The 2D analyses yield similar hoop residual stresses to the 3D analysis, and closely capture the maximum and minimum ID surface hoop residual stresses from the 3D analysis. The primary difference in ID surface residual stresses between the 2D fixed-fixed and 2D fixed-free constraints cases is the higher tensile axial stresses in the pipe outside of the weld region. The 2D analyses under-predict the maximum axial residual stress compared to the 3D analysis. The 2D ID surface residual stress results tend to bound the averaged 3D results. 2D axisymmetric modeling tends to significantly under-predict weld shrinkage. Axial weld shrinkage from 3D modeling is of the same magnitude as values measured in the laboratory on a prototypic mockup.

Finite Element Simulation of Welding Sequences Effect on Residual Stresses in Multipass Butt-Welded Stainless Steel Pipes

2011 ◽  
Vol 134 (1) ◽  
Author(s):  
S. Feli ◽  
M. E. Aalami Aaleagha ◽  
M. Foroutan ◽  
E. Borzabadi Farahani
Keyword(s):  
Finite Element ◽  
Stainless Steel ◽  
Heat Source ◽  
Residual Stresses ◽  
Finite Element Simulation ◽  
3D Model ◽  
Axisymmetric Model ◽  
Element Simulation ◽  
Starting Point ◽  
Welding Sequences

In this paper, a finite element simulation, based on abaqus software is presented for analyzing the temperature history and the residual stress states in multipass welds in stainless steel pipe. The uncoupled thermal–mechanical a three-dimensional (3D) model and a two-dimensional (2D) model are developed. The volumetric heat source with double ellipsoidal distribution for front and rear heat source, proposed by Goldak and Akhlaghi, has also been used. Furthermore, a moving heat source has been modeled by abaqus subroutine DFLUX. A user subroutine FILM has also been used to simulate the combined thermal boundary conditions. The results of both a 3D model and a 2D axisymmetric model which are compared with the available experimental measurements show good agreements. Predictions show that the axial and hoop residual stresses in a 3D model and a 2D axisymmetric model have the same distributions in all locations except the starting point of welding. The effects of welding sequences on the thermal and structural analysis are also investigated. Four types of welding sequences for circular welds of pipe have been used and thermal history and axial and hoop residual stresses are compared. Predictions show that for other locations (except the starting point of welding) there are no important differences of axial and hoop residual stresses for welding sequences and they have the same distribution along axial direction.

A method for the measurement of residual stresses using a fracture mechanics approach

1989 ◽  
Vol 24 (1) ◽  
pp. 23-30 ◽  
Author(s):  
K J Kang ◽  
J H Song ◽  
Y Y Earmme
Keyword(s):  
Residual Stress ◽  
Finite Element ◽  
Stress Distribution ◽  
Fracture Mechanics ◽  
Residual Stresses ◽  
Residual Stress Distribution ◽  
The State ◽  
Two Dimensional ◽  
Finite Element Analyses ◽  
Simple Method

A simple method for measuring residual stresses in a plate is described. In this method residual stresses are evaluated using a fracture mechanics approach, that is, the strains or displacements measured at a point on the edge of a plate as a crack is introduced and extended from the edge are used to deduce the state of stresses that existed in the uncracked plate. Through finite element analyses and experiments this method is shown to be valid and effective for measuring the two-dimensional residual stress distribution of a welded plate.

Sensitivity of Predicted Weld Residual Stresses in the NeT Task Group 1 Single Bead on Plate Benchmark Problem to Finite Element Mesh Design and Heat Source Characteristics

2009 ◽  
Author(s):  
Philip J. Bendeich ◽  
Mike C. Smith ◽  
David G. Carr ◽  
Lyndon Edwards
Keyword(s):  
Finite Element ◽  
Heat Source ◽  
Residual Stresses ◽  
Task Group ◽  
Simple Problem ◽  
Controlled Study ◽  
Design Element ◽  
Benchmark Problem ◽  
Source Characteristics ◽  
Group 1

A single weld bead deposited on a flat plate is a deceptively simple problem that is, in practice, a significant challenge for both measurement and prediction of weld residual stresses. Task Group 1 of the NeT collaborative network has examined this problem in an extensive programme of measurement and simulation extending from 2002 to 2008. Thus, the NeT bead on plate forms an ideal benchmark problem for the development of weld residual stress simulation techniques. It is often difficult to separate the influence of different analysis variables in a large collaborative study such as NeT Task Group 1. This paper examines sensitivity to mesh design, element type, and heat source characteristics in a closely controlled study using several different mesh designs, element types (both tetrahedral and hexahedral), and heat sources, but the same material constitutive model and finite element analysis code. It complements a companion paper that varies material constitutive models. A dedicated heat source modelling tool with a semi-automatic interface to the ABAQUS finite element code has been used to vary the heat source characteristics, thus facilitating rapid and controlled sensitivity studies without the need for bespoke heat source coding within ABAQUS.

Residual Stresses in As-Welded Joints: Finite Element Modeling and Neutron Difraction Stress Measurements

2011 ◽  
Vol 488-489 ◽  
pp. 335-338 ◽  
Author(s):  
Claire Acevedo ◽  
Jean Marie Drezet ◽  
J. P. Lefebvre ◽  
Laurent D'Alvise ◽  
A. Nussbaumer
Keyword(s):  
Residual Stress ◽  
Finite Element ◽  
Residual Stresses ◽  
Arc Welding ◽  
Analysis Method ◽  
Weld Joints ◽  
Stress Components ◽  
Bridge Joints ◽  
Nonlinear Transient ◽  
Welding Processes

This paper describes the numerical analysis method used to estimate welding induced residual stresses in K-shape tubular bridge joints. The knowledge of residual stress distribution is required to design the geometry of K-joints loaded under fatigue stresses. Numerical simulations are focused on the arc welding MAG process, generally used to weld joints in bridge construction. Thermo-mechanical analyses are performed in 3D using two finite element codes:ABAQUS® and MORFEO® . ABAQUS has the advantage to offer large analysis capabilities(nonlinear, transient, dynamic, etc.) whereas MORFEO is more dedicated to welding processes and offers the possibility to analyze crack propagation under fatigue loads. Computed residual stresses in the region surrounding the weld are compared with measured residual stresses in order to estimate the ability of the codes to reproduce these stresses. Position, orientation and magnitude of the highest residual stress components are discussed.

Sign in / Sign up

Export Citation Format

Share Document