Thermomechanical Model of Spot Welding for Calculating Residual Stresses

2003 ◽  
Author(s):  
Lijun Xu ◽  
Jamil A. Khan
Keyword(s):  
Residual Stresses ◽  
Heat Generation ◽  
Spot Welding ◽  
Welding Process ◽  
Mechanical Analysis ◽  
Temperature Dependent ◽  
Thermomechanical Model ◽  
Faying Surface ◽  
Proposed Model ◽  
Electrode Interface

A comprehensive axisymmetric model of the coupled thermal-electrical-mechanical analysis predicting weld nugget development and residual stresses for the resistance spot welding process of Al-alloys is developed. The model estimates the heat generation at the faying surface, the workpiece-electrode interface, and the Joule heating of the workpiece and electrode. The phase change due to melting in the weld pool is considered. The contact area and its pressure distribution at both the faying surface and the electrode-workpiece interface are determined from a coupled thermal-mechanical model using a finite element method. The knowledge of the interface pressure provides accurate prediction of the interfacial heat generation. For the numerical model, temperature dependent thermal, electrical and mechanical properties are used. The proposed model can successfidly calculate the nugget diameter and thickness, and predict the residual stresses and the elastic-plastic deformation history. The calculated nugget shape and the deformation of sheets based on the model are compared with the experimental data. The computed residual stresses approach the distribution of experimental measurement of the residual stress.

Numerical Study of Thermal Modeling of Resistance Spot Welding Utilizing Coupled Thermal-Electrical-Mechanical Analysis

1999 ◽  
Author(s):  
Lijun Xu ◽  
Jamil A. Khan ◽  
Yuh-Jin Chao ◽  
Kirkland Broach
Keyword(s):  
Resistance Spot Welding ◽  
Spot Welding ◽  
Numerical Study ◽  
Mechanical Analysis ◽  
Convective Transport ◽  
Temperature Dependent ◽  
Resistance Spot ◽  
Proposed Model ◽  
Nugget Formation ◽  
Surface Contact Area

Abstract This paper successfully proposes a novel model to predict nugget development during resistance spot welding (RSW) of binary Al-alloys. The model employs a coupled thermal-electrical-mechanical analysis, and also accounts for phase change and convective transport in weld pool. Faying surface contact area and its pressure distribution are simulated from coupled thermal-mechanical model using a finite element method. Temperature dependent thermal, electrical and mechanical properties are used. The proposed model can successfully calculate most of the RSW response in term of nugget diameter and thickness, the extent of heat affected zone, etc. The calculated nugget shape based on the thermal model agrees well with the experimental data. Convection effect due to the interactions between phases in the porous mushy zone and the buoyancy force arising from the temperature difference is determined to be not significant for the weld-nugget formation. The proposed model can be used to optimize RSW process parameters for industrial welding.

Simulations of Residual Stresses in Resistance Spot Welding Process

2010 ◽  
Vol 33 (9) ◽  
pp. 843-857 ◽  
Author(s):  
R. Dalewski ◽  
J. Jachimowicz ◽  
M. Pietrzakowski
Keyword(s):  
Residual Stresses ◽  
Resistance Spot Welding ◽  
Spot Welding ◽  
Welding Process ◽  
Resistance Spot

Thermo-mechanical modelling of the Friction Stir Spot Welding process: Effect of the friction models on the heat generation mechanisms

2022 ◽  
pp. 146442072110709
Author(s):  
Nasra Hannachi ◽  
Ali Khalfallah ◽  
Carlos Leitão ◽  
Dulce Rodrigues
Keyword(s):  
Numerical Simulation ◽  
Heat Generation ◽  
Spot Welding ◽  
Welding Process ◽  
Friction Stir Spot Welding ◽  
Frictional Heat ◽  
Contact Conditions ◽  
Friction Stir ◽  
Friction Models ◽  
Generation Mechanisms

Friction Stir Spot Welding involves complex physical phenomena, which are very difficult to probe experimentally. In this regard, the numerical simulation may play a key role to gain insight into this complex thermo-mechanical process. It is often used to mimic specific experimental conditions to forecast outputs that may be substantial to analyse and elucidate the mechanisms behind the Friction Stir Spot Welding process. This welding technique uses frictional heat generated by a rotating tool to join materials. The heat generation mechanisms are governed by a combination of sliding and sticking contact conditions. In the numerical simulation, these contact conditions are thoroughly dependent on the used friction model. Hence, a successful prediction of the process relies on the appropriate selection of the contact model and parameters. This work aims to identify the pros and cons of different friction models in modelling combined sliding-sticking conditions. A three-dimensional coupled thermo-mechanical FE model, based on a Coupled Eulerian-Lagrangian formulation, was developed. Different friction models are adopted to simulate the Friction Stir Spot Welding of the AA6082-T6 aluminium alloy. For these friction models, the temperature evolution, the heat generation, and the plastic deformation were analysed and compared with experimental results. It was realized that numerical analysis of Friction Stir Spot Welding can be effective and reliable as long as the interfacial friction characteristics are properly modelled. This approach may be used to guide the contact modelling strategy for the simulation of the Friction Stir Spot Welding process and its derivatives.

A Simplified Transient Thermal Analysis of Resistance Spot Welding Process

2010 ◽  
Vol 154-155 ◽  
pp. 443-446
Author(s):  
Zhi Gang Hou ◽  
Jun Zhao ◽  
Li Qiang Xu ◽  
Zhong Guo
Keyword(s):  
Resistance Spot Welding ◽  
Spot Welding ◽  
Complex Structure ◽  
Welding Process ◽  
Temperature Dependent ◽  
Resistance Spot ◽  
Whole Process ◽  
History Of ◽  
Transient Thermal

In order to theoretically simulate the welding process of complex structure with large quantities of welding spots, a simplified method for analyzing a single spot welding should be developed firstly. In this paper, a 2D axisymmetric model of thermoelectric Finite Element Method (FEM) is developed to analyze the transient thermal behavior of Resistance Spot Welding (RSW) process using ANSYS. The determination of the contact resistance at the faying surface is moderately simplified to reduce the calculating time, while the temperature dependent material properties, phase change and convectional boundary conditions are taken into account for the improvement of the calculated accuracy. The thermal history of the whole process and temperature distributions for any position in the weldment is obtained through the analysis. The model can also predict the weld nugget size and the width of the Heat Affected Zone (HAZ).

An Improved Numerical Modeling for Resistance Spot Welding Process and Its Experimental Verification

1998 ◽  
Vol 120 (2) ◽  
pp. 246-251 ◽  
Author(s):  
O. P. Gupta ◽  
Amitava De
Keyword(s):  
Resistance Spot Welding ◽  
Spot Welding ◽  
Hsla Steel ◽  
Low Carbon Steel ◽  
Welding Process ◽  
Current Density Distribution ◽  
Mechanical Analysis ◽  
Electrode System ◽  
Low Carbon ◽  
Resistance Spot

A numerical model of resistance spot welding with spherical tip electrode is developed to incorporate the electro-thermal aspect as well as thermo-elasto-plastic behaviour inherent in this process. The electro-thermal aspect includes the Joule’s resistive heating along the contact surfaces and within the sheet-electrode system due to nonuniform current density distribution in the sheet-electrode. The elasto-plastic deformation of the sheet-electrode interface at higher temperature is included in the thermo-mechanical analysis. The interdependence of those two analyses has been taken care of The model is used to simulate the spot welding in low-carbon steel sheets of 1 mm and 2 mm thickness and HSLA steel sheet of 1 mm thickness. The results are compared with experimental data obtained as a part of this work and also with literature data. The comparison has shown a good agreement in all the cases. The results are later used to draw the thermal cycle curves at different location along the faying surface.

Numerical Simulation on the Temperature Distribution in Resistance Microwelding of Insulated Cu Wire

2012 ◽  
Vol 472-475 ◽  
pp. 1143-1146
Author(s):  
Bing Hua Mo ◽  
Xian Feng Zhang ◽  
Jia Qing Wu ◽  
Zhong Ning Guo
Keyword(s):  
Experimental Data ◽  
Copper Wire ◽  
Mechanical Analysis ◽  
Peltier Effect ◽  
Welding Parameters ◽  
Interface Temperature ◽  
Temperature Dependent ◽  
Molybdenum Electrode ◽  
Proposed Model ◽  
Properties Of Materials

This paper develops a model to simulate wire-to-sheet lapped resistance microwelding (RMW) process. The model employs a coupled thermal–electrical–mechanical analysis and accounts for temperature-dependent thermophysical properties of materials, contact resistance and the Peltier effect. Results show the interface temperature between the molybdenum electrode and copper wire is higher than the faying surface. The predicted thermal distributes agree well with the experimental data. The proposed model can be applied to predict the effects of the welding parameters.

scholarly journals Effect of Boundary Conditions on Residual Stresses and Distortion in 316 Stainless Steel Butt Welded Plate

2019 ◽  
Vol 38 (2019) ◽  
pp. 827-836 ◽  
Author(s):  
Dhayanithi Venkatkumar ◽  
Durairaj Ravindran
Keyword(s):  
Thermal Analysis ◽  
Stainless Steel ◽  
Residual Stresses ◽  
Welding Process ◽  
Physical And Mechanical Properties ◽  
Mechanical Analysis ◽  
Distribution Model ◽  
Fe Method ◽  
Thermal Histories ◽  
Transient Thermal

AbstractIn the present work, the prediction of residual stresses and distortion due to GTA welding process, a Finite Element (FE)Method has been developed and applied. Stainless steel plate of 3mm thickness is taken for the analysis. The prediction of residual stresses and distortion is performed by thermal and mechanical analysis that is sequentially coupled. The thermal analysis and mechanical analysis of the plate subjected to heat source movement have been studied consecutively. The FE analysis is performed in ANSYS software. In transient thermal analysis, Gaussian distribution model has been used for heat input of the arc. During modeling, the physical and mechanical properties that depend on temperature are considered. The heat transfer losses through all the three mechanisms are incorporated. For validating the FE simulated analysis, an experiment is conducted. The predicted thermal histories are very close agreement with measured thermocouple readings. After validation of thermal analysis results, the transient thermal histories are used as input for further mechanical analysis to simulate. The large displacement theory is used to conduct mechanical analysis. The effect of constraints on distortion and residual stresses are numerically studied. The predicted stresses and distortion results of different cases are discussed and presented.

scholarly journals Evaluation of residual stresses in a tube-to-plate welded joint

2019 ◽  
Vol 300 ◽  
pp. 19005 ◽  
Author(s):  
Andrea Chiocca ◽  
Francesco Frendo ◽  
Leonardo Bertini
Keyword(s):  
Residual Stresses ◽  
Numerical Simulations ◽  
Thermal Cycle ◽  
Transient Analysis ◽  
Welded Joint ◽  
Base Material ◽  
Welding Process ◽  
Deep Understanding ◽  
Experimental Tests ◽  
Temperature Dependent

A deep understanding of the manufacturing process is needed in order to achieve safety and quality requirements for parts and components; to this regard, residual stresses play an important role in welded structures. Residual stresses are mainly caused by the extremely severe thermal cycle to which the welded metal and base material are subjected to during welding process and their knowledge leads to a better static and fatigue assessment of welded joints. This work deals with the study of residual stresses for a tube to plate T-joint, made of S355JR carbon steel. The work was carried out by both numerical simulations and experimental tests. The numerical simulations were performed by Ansys FE code through a structural-thermal full transient analysis to evaluate stress, strain and temperature in each node at each step of the simulation. The “birth and death” method was employed, together with temperature-dependent material properties.A2Danda3D simulation were performed, in order to evaluate possible differences due to the welding process. Numerical results were compared to some preliminary measurements obtained through an incremental cut made on the plate.

Thermal Modeling of Polymerizing Polymethylmethacrylate, Considering Temperature-Dependent Heat Generation

1992 ◽  
Vol 114 (2) ◽  
pp. 251-259 ◽  
Author(s):  
B. R. Baliga ◽  
P. L. Rose ◽  
A. M. Ahmed
Keyword(s):  
Heat Conduction ◽  
Heat Generation ◽  
Thermal Modeling ◽  
Finite Volume Methods ◽  
Test Problems ◽  
Temperature Dependent ◽  
Scanning Calorimetry ◽  
Proposed Model ◽  
Volumetric Rate ◽  
Radial Heat

A methodology for the modeling of unsteady heat conduction in polymethylmethacrylate (PMMA) during its exothermic polymerization is presented. The emphasis is on the formulation of a model for the volumetric rate of heat generation, including its temperature-dependent characteristics. Three parameters appear in the proposed model. The empirical determination of these parameters using Differential Scanning Calorimetry is demonstrated. The incorporation of the proposed model into finite volume methods is also demonstrated, in the context of unsteady, onedimensional, radial heat conduction in cylindrical coordinates. In addition, the application of the proposed model to two test problems is presented and discussed. The results are encouraging, and the proposed methodology appears to be applicable to the thermal modeling of exothermic polymerization processes in general.

Effect of Thermal Input on Finite Element Predictions of Welding Residual Stresses

2011 ◽  
Vol 399-401 ◽  
pp. 1976-1983
Author(s):  
Ai Hui Wu ◽  
Stavros Syngellakis ◽  
B. G. Mellor
Keyword(s):  
Finite Element ◽  
Residual Stresses ◽  
Welded Joint ◽  
Welding Process ◽  
Mechanical Analysis ◽  
Two Dimensional ◽  
Distribution Modelling ◽  
Element Simulation ◽  
Key Factor ◽  
Dimensional Finite Element

A two-dimensional finite element simulation of a welding process is developed for predicting temperature histories and residual stresses in a structural steel butt-welded joint. The purpose of the simulation presented in this paper is the assessment of the effect of uncertainties in thermal material, loading and constraint input on both the thermal and mechanical analysis predictions. The model is validated by comparison with previously welded and tested specimen with published residual stresses measurements. Residual stress results are not sensitive to the thermal analysis input even if the latter has significant influence on temperature distribution. Modelling boundary conditions for both thermal and stress analyses, was identified as a key factor affecting predictions of residual stresses and distortion.

Sign in / Sign up

Export Citation Format

Share Document