Visco-Elastic-Plastic Constitutive Model for A7N01-T6 Alloy Welding and Analytical Solutions with Finite Element Codes

2013 ◽  
Vol 446-447 ◽  
pp. 284-287
Author(s):  
K.J. Song ◽  
Y.H. Wei ◽  
Z.B. Dong ◽  
K. Fang ◽  
W.J. Zheng ◽  
...  
Keyword(s):  
Finite Element ◽  
Plastic Strain ◽  
Constitutive Model ◽  
Strain Hardening ◽  
Strain Softening ◽  
Great Influence ◽  
Welding Process ◽  
Welding Residual Stress ◽  
Creep Equation ◽  
Maximum Deformation

This paper has established a viscoelasticplastic constitutive model for A7N01T6 alloy welding, which is temperature and deformation history dependent. The model uses elasticmixed hardening plastic and creep equation to describe the strain hardening at low temperatures and strain softening at high temperatures, respectively. Then it is applied for finite element numerical simulation of the welding process. By comparison with the conventional temperature dependent elasticperfectly plastic model, the overall longitudinal residual compressive plastic strain and the maximum deformation of welding sheet are larger. This is because that the plastic strain is mostly produced in high temperature range. Strain softening has great influence on the evolution of plastic strain. The compressive plastic strain during heating is larger than the tensile plastic strain during cooling. Strain hardening effect on welding residual strain and stress is almost negligible. Using the established constitutive model, welding residual stress and strain are in good agreement with the theoretical results.

A Characteristic and a Precisely Constitutive Model for Undrained Clay

2020 ◽  
Vol 975 ◽  
pp. 203-207
Author(s):  
Shih Tsung Hsu ◽  
Wen Chi Hu ◽  
Yu Heng Lin ◽  
Zhuo Ling
Keyword(s):  
Shear Strength ◽  
Plastic Strain ◽  
Constitutive Model ◽  
Strain Hardening ◽  
Undrained Shear Strength ◽  
Triaxial Tests ◽  
Stress Strain ◽  
Proposed Model ◽  
Taipei Basin ◽  
Undrained Shear

Constitutive models for soils are usually adopted in numerical method to analyze the behavior of geotechnical structures. This study performs a series of consolidated-undrained triaxial tests to establish the stress-strain curve of clay. A constitutive model that considers continuous strain hardening-softening is proposed based on the results of triaxial tests. Triaxial test results reveal that undrained shear strength linearly increases with an increase in consolidated pressure , the normalized undrained shear strength is about 0.52 not only for this study but also for the other two cases around Taipei Basin. Due to undrained condition, an associated flow rule between plastic strain increment and stress tensor is adopted. As accumulative plastic strain or/and consolidated pressure change, the mobilized undrained shear strength also changes. All parameters needed for the proposed model can be expressed as a function of undrained shear strength Su, The mobilized undrained shear strength for the proposed model during strain hardening-softening can be in term of accumulative plastic strain. This model can calculate the stress-strain curves of clayed soils accurately.

Bodner-Partom Constitutive Model and Nonlinear Finite Element Analysis

1990 ◽  
Vol 112 (3) ◽  
pp. 287-291 ◽  
Author(s):  
F. A. Kolkailah ◽  
A. J. McPhate
Keyword(s):  
Experimental Data ◽  
Finite Element ◽  
Plastic Strain ◽  
Constitutive Model ◽  
Finite Element Model ◽  
Numerical Technique ◽  
Element Model ◽  
Material Behavior ◽  
Model Parameters ◽  
Elastic Plastic

In this paper, results from an elastic-plastic finite-element model incorporating the Bodner-Partom model of nonlinear time-dependent material behavior are presented. The parameters in the constitutive model are computed from a leastsquare fit to experimental data obtained from uniaxial stress-strain and creep tests at 650°C. The finite element model of a double-notched specimen is employed to determine the value of the elastic-plastic strain and is compared to experimental data. The constitutive model parameters evaluated in this paper are found to be in good agreement with those obtained by the other investigators. However, the parameters determined by the numerical technique tend to give response that agree with the data better than do graphically determined parameters previously used. The calculated elastic-plastic strain from the model agreed well with the experimental strain.

Analysis on the Welding Thermal Field and Residual Stress of Thick Plate

2015 ◽  
Vol 1095 ◽  
pp. 693-697
Author(s):  
Jiu Hong Jiang ◽  
Qiang Wang ◽  
Wen Lv
Keyword(s):  
Residual Stress ◽  
Finite Element ◽  
Thick Plate ◽  
Thermal Field ◽  
Welding Process ◽  
Source Model ◽  
Simulation Software ◽  
Welding Residual Stress ◽  
Element Simulation ◽  
Thick Steel

A 60mm Q345 rigid thick plate with V groove welding connection was modeled in order to simulate the welding residual stress by finite element method. Both element birth and death technique and double ellipse heat source model were introduced to simulate the welding process. The welding thermal field and residual stress of thick steel plate were analyzed by finite element simulation software ANSYS.Then the thermal field and residual stress distribution were visually demonstrated. The result shows that the thermal field shaped like a spindle during welding period and the residual stress at the mid-section in lateral, longitudinal and thickness direction of the welding joint is lower than the stress at the surface of the welding connection.

scholarly journals Estimation formula for residual stress from the blind-hole drilling method

2018 ◽  
Vol 10 (8) ◽  
pp. 168781401878740 ◽  
Author(s):  
Chi-Liang Kung ◽  
Ah-Der Lin ◽  
Po-Wei Huang ◽  
Chao-Ming Hsu
Keyword(s):  
Residual Stress ◽  
Finite Element ◽  
Welding Process ◽  
Welding Residual Stress ◽  
Hole Drilling ◽  
Parameter Group ◽  
Blind Hole ◽  
Finite Element Software ◽  
Inconel 690 ◽  
Stress Components

In this study, the accuracy of blind-hole method on weld residual stress estimation is investigated. A modified parameter group has also proposed to improve the accuracy. The thermal-elastic-plastic finite element model is employed to build up the residual stress distribution and the blind-hole process. The MSC Marc finite element software package is used to simulate the welding process and the welding residual stress and strain distributions around the weld of two inconel 690 alloy plates filled with I-52 GTAW filler. Then the process of the traditional blind hole is simulated by employing the inactive elements. The data of the residual strain variations of strain gages located around the blind hole is introduced into the blind-hole method to estimate the original residual stress components at the hole center. The effects of drilling depth, drilling size, gage radius, gage position, and the distance on the accuracy of estimated residual stress have also been studied and discussed. Based on the residual stress components simulated from the welding process, a modified stress parameter group has also been proposed to improve the accuracy of blind-hole method. Numerical results indicate that the accuracy of estimated residual stress can be improved significantly by employing the proposed blind-hole parameters.

scholarly journals Finite Element Prediction of Residual Stress Distributions in a Multipass Welded Piping Branch Junction

2006 ◽  
Author(s):  
Wei Jiang ◽  
Kadda Yahiaoui
Keyword(s):  
Residual Stress ◽  
Finite Element ◽  
Residual Stresses ◽  
Welding Process ◽  
Pressure Vessels ◽  
Welding Residual Stress ◽  
Stress Distributions ◽  
Multipass Welding ◽  
Hexahedral Elements ◽  
Element Removal

Piping branch junctions and nozzle attachments to main pressure vessels are common engineering components used in the power, oil and gas, and shipbuilding industries amongst others. These components are usually fabricated by multipass welding. The latter process is known to induce residual stresses at the fabrication stage which can have severe adverse effects on the in-service behavior of such critical components. It is thus desirable if the distributions of residual stresses can be predicted well in advance of welding execution. This paper presents a comprehensive study of three dimensional residual stress distributions in a stainless steel tee branch junction during a multipass welding process. A full 3D thermo-mechanical finite element model has been developed for this purpose. A newly developed meshing technique has been used to model the complex intersection areas of the welded junction with all hexahedral elements. Element removal/reactivate technique has been employed to simulate the deposition of filler material. Material, geometry and boundary nonlinearities associated with welding were all taken into account. The analysis results are presented in the form of stress distributions circumferentially along the weldline on both run and branch pipes as well as at the run and branch cross sections. In general, this computational model is capable of predicting 3D through thickness welding residual stress, which can be valuable for structural integrity assessments of complex welded geometries.

Detailed Contact Analysis of the J-Tube Riser Pull-In Method

2011 ◽  
Author(s):  
Farzad Farid-Afshin ◽  
Christian Reva ◽  
Erlend R. Vistnes
Keyword(s):  
Finite Element ◽  
Plastic Strain ◽  
Constitutive Model ◽  
General Purpose ◽  
Friction Model ◽  
Contact Analysis ◽  
Von Mises Stress ◽  
Contact Friction ◽  
Offshore Platforms ◽  
Element Analysis

J-tube method of riser installation is a conventional method of connecting the subsea pipelines to fixed offshore platforms which are abundant in the Norwegian and international waters. The integrity of the J-tube, its supports, riser itself and the platform has to be maintained during pull-in of a riser into a J-tube. To ensure this, it is required that the pull-in and reaction forces, in addition to the riser plastic strain and J-tube stresses should be established either by detailed finite element contact analysis or by simplified methods available in literature. With the advances made in the finite element procedures and tools in the past decades and due to the higher degree of accuracy that they can capture, the contact analysis is often the preferred approach. Various parameters contribute to the riser pull-in operation which should be represented accurately in a finite element analysis to provide reliable results. Among others, they include the riser back tension (lay tension, seabed friction, etc.), riser J-tube friction, riser material’s yield stress and constitutive model, riser and J-tube fabrication tolerances, boundary conditions, clearances, etc. In addition, there are numerical modeling parameters such as the friction model (contact friction-clearance/overclosure relationship) and the details of the material’s constitutive model which can affect the accuracy and convergence of the analyses. In this paper, the general trends of response are presented with respect to physical variations of these parameters. Pull-in force, J-tube equivalent von-Mises stress and riser plastic strain are the response indicators which are studied. Analyses are performed using ABAQUS general-purpose finite element package [1]. The conclusions based on the observed trends can help to decide these input parameters as every individual project (i.e. study, detailed phase, etc.) and client requires.

Structure Optimization and Welding Residual Stress Analysis of Twin-Web Turbine Disc

2012 ◽  
Vol 622-623 ◽  
pp. 309-314 ◽  
Author(s):  
Xiu Li Shen ◽  
Shao Jing Dong
Keyword(s):  
Residual Stress ◽  
Weight Loss ◽  
Finite Element ◽  
Numerical Calculation ◽  
Stress Analysis ◽  
Welding Process ◽  
Structure Optimization ◽  
Welding Residual Stress ◽  
Turbine Disc ◽  
Residual Stress Analysis

This paper has proposed a new shape of the twin-web turbine disc. Based on a design optimization of the shape of the twin-web turbine disc by finite element numerical calculation, we analyzed welding types and carried out the simulation of the welding process and obtained the residual stress. Finally we got a 5.8% weight loss and summarized residual stress of the welding and proved the feasibility of the new shape.

Influence Analysis of Welding Residual Stress for Seismic Behavior to Side-Plate Reinforced Section

2012 ◽  
Vol 256-259 ◽  
pp. 2074-2078
Author(s):  
Yun Liu ◽  
Cheng Chao Mao ◽  
Yong Jie Song ◽  
Xue Jing Song
Keyword(s):  
Residual Stress ◽  
Finite Element ◽  
Seismic Behavior ◽  
Welding Process ◽  
Welding Residual Stress ◽  
Finite Element Models ◽  
Side Plate ◽  
Research Objects ◽  
Seismic Index ◽  
Element Method

Taking side-plate reinforced section as research objects, this paper establishes the models by Ansys non-linear finite element method and simulates welding process of with birth-death element method. Comparing the different seismic index among test specimen and finite element models that based on whether or not considering welding residual stress, based on which, this research draws a conclusion that the influence of welding residual stress for seismic behavior to side-plate reinforced section is not obvious.

Finite Element Simulative Analysis on the Influence of Solid-State Transformation on Welding Residual Stress

2013 ◽  
Vol 785-786 ◽  
pp. 1229-1235 ◽  
Author(s):  
Chun Run Li ◽  
Zhi Peng Zhang ◽  
Yi Ming Zhang ◽  
Zong Tao Fang
Keyword(s):  
Residual Stress ◽  
Finite Element ◽  
Solid State ◽  
Phase Change ◽  
Weld Zone ◽  
Thermal Strain ◽  
Welding Process ◽  
Welding Residual Stress ◽  
State Transformation ◽  
Solid State Transformation

This paper takes the Q345 steel as an example, adopting finite element simulative analysis to study the influence of solid-state transformation on welding residual stress. By setting the value of the thermal strain in different temperature, the change in volume caused by the phase changes is equivalent to the thermal strain. Simulation includes two cases which are consideration of phase transformations and not consideration. The results showed that the distribution trend of the longitudinal stress of the weld zone is substantially the same in the two simulations. In the case of not consider the simulation of phase change, there is a lot of stress in the weld zone and the heat affected zone and the maximum value could be 427 MPa. In regard to transverse stress, phase change not only affects the value of the stress, but also changes the direction of the stress of the weld middle portion. Welding residual stress is also measured by X-ray. Phase change simulation and experimental results are in good agreement, it can be concluded that phase change in the welding process will result in a significant impact on the distribution of the residual stress, which could not be ignored in the finite element simulation of welding process.

Sign in / Sign up

Export Citation Format

Share Document