Showing 9 results for Simulation
B. Sadeghian, M. Atapour, A. Taherizadeh ,
Volume 1, Issue 1 (1-2016)
Abstract
Today, steel to aluminum joints are used to facilitate transportation and fuel consumption. These joints are applied from nuclear, aerospace and naval to automobile and kitchen industries. According to previous studies fusion welding processes are not suitable methods for these joints, solid-state welding, especially friction stir welding, is a proper way to use for these joints. However, using this method for these two metals needs adequate prediction of temperature distribution and material flow to obtain enhanced joints. In this study, a finite element method is used to predict the temperature distribution. In addition, a computational fluid dynamics solution is coupled with the thermal solution. Therefore, the flow rate, strain rate and dynamic viscosity is obtained. Also, the joint morphology is predicted using the Level Set method. It is shown the material flow depends on flow rate, strain rate and dynamic viscosity and is intensively function of rotational speed. Additionally, offset to the aluminum side improves the morphology of the stir zone.
Dr M. Safari, Dr H. Mostaan,
Volume 1, Issue 1 (1-2016)
Abstract
Weldability of high carbon steels due to the high percentage of carbon and consequently formation of martensitic structure is very poor. In this research, resistance spot welding of eutectoid high carbon steel 1075 is experimentally and numerically investigated from various points of view. The effect of welding current as one of the most effective parameters on failure mode, mechanical properties and nugget size diameter in resistance spot welding is analyzed with experimental tests and numerical simulations. The results show that with increase of welding current, the diameter of nugget size is increased and consequently the failure mode changes from interfacial mode to pull out mode.
A. Rezaei, E. Ranjbarnodeh, M. Iranmanesh,
Volume 1, Issue 1 (1-2016)
Abstract
Fusion welding is widely used in heavy industries to join different parts together. But sometimes welding-induced distortions cause problems like misalignment during assembling and make costs to remove them. Thus it is imperative to predict and mitigate them to improve weldments quality and also reduce in fabrication costs. This study at first will introduce inherent deformation method for prediction of welding-induced distortion. In following a relatively large panel will be simulated by finite element software ANSYS and its distortion will be calculated. The results will be compared by experimental measurement. Afterward this investigation will present an efficient welding sequence which produce minimal distortion.
H. Aghajani Derazkola, M. Hosseinzadeh, M. Elyasi,
Volume 3, Issue 1 (8-2017)
Abstract
In this study, the effects of linear speed and rotational speed of the friction stir welding tool was investigated on the heat generation and distribution of heat,the material flow and weld defect formation of the Polyamide 6 (PA6) workpiece. The commercial CFD Fluent 6.4 software package was used to the simulation of the process with computational fluid dynamic technique. The output results of the simulation showed higher proportion of rotational speed to the tool linear speed, the material flow in front of the friction stir welding tool became more and the dimension of the welding stir zone became bigger. The maximum simulating generated heat was 220 centigrade degrees and the maximum head and material flow were observed at the advancing side of the join surface. The obtained simulation results were compared with other researchers' experimental results and the simulation outputs displayed acceptable agreement with experimental results.
M. E. Kazemian, F. Mohsenifar, R. Ghanbarzadeh,
Volume 3, Issue 1 (8-2017)
Abstract
In this paper, laser beam welding of a rectangular piece of steel was simulated using Fluent software. Physical properties of analytical field was constant and its changes with temperature was ignored. In the present work, effect of tool speed and laser power on temperature distribution of workpiece surface and different deeps in the plane of symmetry and also maximum of temperature and depth of penetration were investigated. Using a macro code, geometry generation and meshing of the analytical field by helping required geometric parameters were provided for software. Moreover, laser radiation power was exerted by writing an UDF in the fluent software. In this case, it was assumed that the workpiece is stationary and gaussian thermal source model defined in UDF moves with the intended speed. Results show that at a constant power, maximum temperature of the workpiece decreases with increasing heat source speed, moreover, in this case, gradient of temperature in front of the workpiece and behind of it, increases and decreases respectively. It is found that the temperature in the depth of the workpiece increases with increasing the power.
, M. Ahl Sarmadi, M. Atapour, A. Behjat, H. Edriss, M. Vahman ,
Volume 4, Issue 1 (8-2018)
Abstract
Galvanic corrosion is an ever-present problem in all different environments, particularly in tanks. The goal of this project is to develop a finite element model that can be used with experimental data to characterize the corrosion of a galvanic weldments couple in an electrolyte. In this study sample are welded by gas tungsten arc welding and friction stir welding. According to ASTM G8, Evaluation of corrosion properties examined with cyclic polarization test in 0.5 molar H2SO4 andthe information required to validate the model was prepared. The finite element model is developed using COMSOL and Math Module through derivation of equations describing corrosion thermodynamics and electrochemical kinetics. The results showed that reducing in heat input to improve galvanic corrosion behavior in the weld sample.In addition to result of simulation reveal sample that welded by gas tungsten arc method had higher current density galvanic corrosion in comparison with friction stir sample.
S. Shadkam, E. Ranjbar Nodeh, M. Iranmanesh,
Volume 5, Issue 2 (1-2020)
Abstract
Increasingly, Welding is used in industry for assembled various products, such as ships, cars, trains and bridges. Welding distortion often results such as lack of accuracy during assembly and will have increases manufacturing costs. So, predict and reduce welding distortion is very important to improve the quality of welded structures. In this study, firstly, a prediction method of welding distortion, which merges thermo-elastic-plastic finite element method (FEM) and large deformation elastic FEM based on inherent strain theory, was developed. Secondly, the inherent deformations of weld joints in a large thin plate panel structure were calculated using the thermo-elastic-plastic FEM and their specifications were also examined. Then, using the obtained inherent deformations, the usefulness of the proposed elastic FEM was demonstrated through the prediction of welding distortion in the large thin plate panel structures. Finally, the influences of welding sequence on distortion were investigated. The results of elastic analysis shows distortion in edges and interior parts of the panels, that can be reduced by changing welding sequence to symmetrical welding sequence.
N. Habibi, H. Eskandari,
Volume 5, Issue 2 (1-2020)
Abstract
Welded tubular joints are widely used in various industry structures for high efficiency subjected to pressure, bending and twisting.Welded structures are the main parts of structures, buildings, bridges, gas pipes, pressure vessels and power transmission equipment in the ship building, construction, oil, gas, petrochemical industries and power plants.A sample of pipe-welded joints is a X-tubular joint that has been investigated in this study.The main objective of the present work is to investigate the heat transfer and residual stress caused by the three-stage welding process in X-tubular joint made of St52 using Simufact Welding software.The welding process involves three welding steps using arc welding. The finite element model contains the thermal and mechanical properties of base metal and welding metal as a function of temperature.Also, advanced modeling tools such as mesh adaptation during the process and meshing compatible with the welding site, the birth and death technique of the element and the source of heat transfer have been used.Welding simulation showed that significant residual stresses were created in the joint after welding. Comparison of the results shows that the numerical results and empirical measurements are in good agreement with each other and the existing model can provide a good prediction of temperature distribution and stress control in this welding process.
A. Ghandi, M. Shamanian, M. R. Salmani3,
Volume 6, Issue 1 (8-2020)
Abstract
The structural and hardness developed in advanced high-strength steel DP590 have been investigated with the help of optical microscopy and scanning electron microscopy on resistance spot welded specimens. The hardness diagram of the weld sections was prepared by microhardness test and the temperature peak and heat distribution were simulated by menas of the Abaqus software. The results show that according to the temperature generated in each region of the weld nugget, the HAZ and base metals have different microstructures, and these difference affects the hardness of the regions. The presence of tempered martensite islands with a fraction of 44% in ferrite matrix in base metal, mainly martensitic structure in the nugget, and martensitic structure along with scattered areas of ferrite in the HAZ was observed. The results of the microhardness tests showed difference in hardness values of the regions, and also it was observed that the hardness values increased in the HAZ and weld zone. The hardness values measured in the nugget, base metal, and HAZ were around 400, 200, and 450 HV which were in accordance with the observed structures
