Million-Finite-Element-Order Large-Scale Computation of Residual Stress in Complicated Weld Structures

2010 ◽  
Author(s):  
Masahito Mochizuki ◽  
Shinsuke Itoh
Keyword(s):  
Residual Stress ◽  
Finite Element ◽  
Large Scale ◽  
Base Plate ◽  
Computational Method ◽  
Element Order ◽  
Welding Deformation ◽  
Weld Distortion ◽  
Steam Separator ◽  
Reactor Internals

Shroud head in a steam separator of ABWR is connected to more than 300 pipes, which are attached by fillet welds. Although the welding causes welding deformation, it is impossible to correct this deformation to the shroud head because the shroud head material is very thick; more than 50 mm. Thus, it is necessary to clarify the mechanism of welding deformation so that it can be quantitatively predicted and controlled. SCC prevention is also essential by residual stress control in reactor internals. The objective of this paper is to predict welding deformation and residual stress for a shroud head, and to investigate the influence of factors such as the inclination angle of the base plate, to which the pipes are connected, on welding deformation and residual stress. Million-finite-element-order large-scale computational method of residual stress and weld distortion has been developed in order to apply directy to complicated weld structures. Details of algorithm and some applications are introduced.

Study on Welding Deformation and Residual Stress of H-Section Beam Based on Finite Element Method

2017 ◽  
Vol 753 ◽  
pp. 305-309 ◽  
Author(s):  
Xu Lu
Keyword(s):  
Mechanical Properties ◽  
Residual Stress ◽  
Finite Element ◽  
Source Parameters ◽  
Welding Process ◽  
Steel Structure ◽  
Bottom Plate ◽  
Welding Deformation ◽  
Element Simulation ◽  
Main Components

The welding H-section beam has good mechanical properties with its superior structure. So they become the main components of steel structure and have been widely used. In this paper, the welded H-section beam is used as the research object. The finite element simulation model is established. The heat source parameters are determined. The deformation of the steel due to the welding process is studied. The results show that the bottom plate and the bottom plate inward bending is about 2.32mm cause by welding process. The residual stress can reach 400MPa.

Finite Element Simulation of Welding of Large Structures

1992 ◽  
Vol 114 (4) ◽  
pp. 441-451 ◽  
Author(s):  
S. Brown ◽  
H. Song
Keyword(s):  
Residual Stress ◽  
Finite Element ◽  
Finite Element Simulation ◽  
Three Dimensional ◽  
Mechanical Analysis ◽  
Welding Distortion ◽  
Surrounding Structure ◽  
Element Simulation ◽  
Weld Distortion ◽  
Welding Processes

Current simulations of welding distortion and residual stress have considered only the local weld zone. A large elastic structure surrounding a weld, however, can couple with the welding operation to produce a final weld state much different from that resulting when a smaller structure is welded. The effect of this coupling between structure and weld has the potential of dominating the final weld distortion and residual stress state. This paper employs both two-and three-dimensional finite element models of a circular cylinder and stiffening ring structure to investigate the interaction of a large structure on weld parameters such as weld gap clearance (fitup) and fixturing. The finite element simulation considers the full thermo-mechanical problem, uncoupling the thermal from the mechanical analysis. The thermal analysis uses temperature-dependent material properties, including latent heat and nonlinear heat convection and radiation boundary conditions. The mechanical analysis uses a thermal-elastic-plastic constitutive model and an element “birth” procedure to simulate the deposition of weld material. The effect of variations of weld gap clearance, fixture positions, and fixture types on residual stress states and distortion are examined. The results of these analyses indicate that this coupling effect with the surrounding structure should be included in numerical simulations of welding processes, and that full three-dimensional models are essential in predicting welding distortion. Elastic coupling with the surrounding structure, weld fitup, and fixturing are found to control residual stresses, creating substantial variations in highest principal and hydrostatic stresses in the weld region. The position and type of fixture are shown to be primary determinants of weld distortion.

scholarly journals Computationally Efficient Models of High Pressure Rolling for Wire Arc Additively Manufactured Components

2021 ◽  
Vol 11 (1) ◽  
pp. 402
Author(s):  
Valeriy Gornyakov ◽  
Yongle Sun ◽  
Jialuo Ding ◽  
Stewart Williams
Keyword(s):  
Residual Stress ◽  
Finite Element ◽  
High Pressure ◽  
Large Scale ◽  
Control Model ◽  
Short Length ◽  
Computational Time ◽  
Element Analysis ◽  
Transient Model ◽  
Wire Arc Additive Manufacturing

High pressure multi-layer rolling is an effective method to reduce residual stress and distortion in metallic components built by wire arc additive manufacturing (WAAM). However, the mechanisms of the reduction in residual stress and distortion during multi-layer rolling are not well understood. Conventional finite element models for rolling are highly inefficient, hindering the simulation of multi-layer rolling for large WAAM components. This study aims to identify the most suitable modelling technique for finite element analysis of large WAAM component rolling. Four efficient rolling models were developed, and their efficiency and accuracy were compared with reference to a conventional large-scale rolling model (i.e., control model) for a WAAM built wall. A short-length transient model with fewer elements than the control model was developed to reduce computational time. Accurate predictions of stress and strain and a reduction in computational time by 96.5% were achieved using the short-length model when an implicit method for numerical solution was employed, while similar efficiency but less accurate prediction was obtained when an explicit solution method was adopted. A Eulerian steady-state model was also developed, which was slightly less efficient (95.91% reduction in computational time) but was much less accurate due to unrealistic representation of rolling process. The applicability of a 2D rolling model was also examined and it was found that the 2D model is highly efficient (99.52% time reduction) but less predictive due to the 2D simplification. This study also shows that the rigid roller adopted in the models is beneficial for improving efficiency without sacrificing accuracy.

Research on Deformation Model of Welding Material Based on Inherent Strain Finite Element Prediction Method

2020 ◽  
Vol 980 ◽  
pp. 58-69
Author(s):  
Wen Cheng Wang ◽  
Lisong Tang ◽  
Feng Wang
Keyword(s):  
Finite Element ◽  
Large Scale ◽  
Plate Thickness ◽  
Prediction Method ◽  
Simulation Software ◽  
Deformation Model ◽  
Welding Deformation ◽  
Element Simulation ◽  
Inherent Strain ◽  
Finite Element Prediction

The paper first introduces the concept of inherent strain and the theory and method of predicting welding deformation by the inherent strain finite element method. Studies have shown that the inherent strain exists in the weld and the near seam area, and it is also related to factors such as welding heat input and plate thickness. Through the use of large-scale finite element simulation software ANSYS, the inherent strain finite element prediction method is applied to the welding deformation of the outer gantry assembly material of forklift, which provides effective reference data for future welding work of forklift gantry materials.

Analysis of Residual Stress in Laser Welded Aerospace Aluminium T-Joints by Neutron Diffraction and Finite Element Modelling

2008 ◽  
Vol 571-572 ◽  
pp. 355-360 ◽  
Author(s):  
Funda S. Bayraktar ◽  
Peter Staron ◽  
Mustafa Koçak ◽  
Andreas Schreyer
Keyword(s):  
Residual Stress ◽  
Finite Element ◽  
Neutron Diffraction ◽  
Residual Stresses ◽  
Fe Simulation ◽  
Base Plate ◽  
Experimental Results ◽  
Finite Element Software ◽  
Two Samples ◽  
First Results

The residual stress distribution in three laser welded T-joint configurations of aerospace aluminium alloys were measured using neutron diffraction and FE-simulation was conducted to compare with the experimental results. A 2 mm thick AA 6013 T6 sheet (as clip) was welded to a 4.5 mm thick and 400 mm wide AA 6156 T4 base plate (as skin of the airframe). In two samples, the thickness of the plate was reduced in some areas after welding to produce so-called “pockets” with the purpose of the weight reduction to resemble the fabrication practise in aircraft industry. The effect of pocketing process, which produced two different geometries around the clip weld on the residual stress evolution was analysed. In the plain sample (without pockets), residual stresses were predicted using the SYSWELD finite element software. The strain measurements on the base plate were performed at three locations; namely, the middle of the weld length (mid-clip), welding start (run-in) and end (run-out) locations. In all welded plates, slightly higher longitudinal tensile residual stresses were detected at the midclip locations, whereas transverse residual stresses were similar for all locations. In the run-out location, higher longitudinal tensile residual stresses were present than in the run-in location, which was the case in our previous results on other samples. The first results of the SYSWELD FE-simulation of the plain sample were compared with experimental results. The comparison has shown particularly good agreement for the transverse stresses. Although the simulation yields higher longitudinal tensile stresses than the experimental results, the stress distributions were very similar.

Prediction of Welding Residual Stress by Using Thermo-Metallurgical-Mechanical Constitute Model

2013 ◽  
Vol 834-836 ◽  
pp. 791-794
Author(s):  
Yu Jie Sun ◽  
Yu Lu ◽  
Jian Xu ◽  
Chun Ming Shi
Keyword(s):  
Residual Stress ◽  
Finite Element ◽  
High Stress ◽  
Element Model ◽  
Computational Method ◽  
Welding Residual Stress ◽  
Butt Welding ◽  
Finite Element Software ◽  
Welding Arc ◽  
Constitute Model

The objective of this paper is to investigate the effects of solid-state phase transformation on welding residual stress in high stress low alloy steel. In this study, based on commercial finite element software, a sequentially coupled thermal, metallurgical, mechanical plane strain finite element model is developed. The main effort is to develop a series of subroutines which consider the heat transfer from welding arc and numerical implementation of a thermo-metallurgical-mechanical constitute equation. The effectiveness of developed computational method is confirmed by a butt welding simulation. Simulation of butt welding demonstrates that the distribution pattern of longitudinal residual stresses perpendicular to weld centerline at the upper surface of weldment has two peak and transformation plasticity has significant effect on the evolution of residual stress.

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