Numerical Simulation Of Welding Process Research Articles

Effect of different friction coefficient models on numerical simulation of inertia friction welding of 2219 Al alloy to 304 stainless steel

In inertia friction welding (IFW) of Al alloy to steel, the friction coefficient of interface influences the friction heat production and determines the accuracy of the numerical simulation of welding process. A fully coupled three-dimensional model was established to simulate the IFW process of 2219 Al alloy to 304 stainless steel. By taking different simplifications in the influencing factors (i.e., temperature, sliding velocity, and pressure) of friction coefficient, three types of friction coefficient models were established and utilized in the simulation of IFW process. The strain compensated Arrhenius and Johnson-Cook models were employed to describe the deformation behavior of Al alloy and steel, respectively. Both Al alloy and steel were assumed to be the elastic-plastic body, and the friction stress was calculated by the Coulomb friction model. The friction interface temperature, angular velocity attenuation, axial shortening distance, and joint appearance were measured to verify and compare the accuracy of the established models. The temperature and stress evolutions during the IFW process were also analyzed. With the smallest error in validation, the friction coefficient model, which was a function of temperature, sliding rate, and pressure, showed the best accuracy in describing the friction behavior. By considering the effect of pressure, a more accurate shear stress at the center region of the interface was calculated with a lower value. It means that the friction resistance at the region was lower, promoting the flow of internal Al alloy and the formation of curly-shape flash.

Mechanism and numerical simulation analysis of laser welding 5182 aluminum alloy/PA66 based on surface texture treatment

The direct connection of dissimilar materials is a hot topic in current research. 5182 aluminum alloy and 30 % glass fiber reinforced PA66 are two commonly used materials in automobile body production. The metal surface is pretreated before laser welding to improve the connection strength of metal and plastic. The influence of laser process parameters on the connection mechanism of dissimilar materials is studied, and the connection mechanism is further explained by numerical simulation of welding process. The results show that the laser input energy increases with the increase of laser power and the decrease of welding velocity. The laser input energy affects the melting of plastic and the filling effect of micro-structures. The filling effect of molten plastic on micro-structures is improved with the increase of laser input energy. The connection strength is increased from 951 N to 1341 N. The thermal decomposition of plastic will produce welding defects when the laser input energy is too high, which will be detrimental to welding strength.

Prediction of welding residual stress and distortion in multi-layer butt-welded 22SiMn2TiB steel with LTT filling metal

The objective of this study is to investigate the influence of low transformation temperature (LTT) filling metal on residual stress and distortion in multi-layer butt-welded 22SiMn2TiB steel. A three-dimensional thermal elastic–plastic finite element model is developed for LTT filling metals, and metallurgical phase transformation is taken into account to predict the martensite fraction of the weld metal. A thermodynamic-based method is employed to calculate martensite start temperature (Ms) and the influence of dilution on Ms is also considered. Volume change due to austenite transformation during heating and martensite transformation during cooling are coupled with the numerical simulation of welding process. The evolution of welding residual stress and welding distortion are both predicted. The simulation results revealed that the distortion of welding plate using LTT filling metal is much smaller than that using austenitic metal. In the weld zone, transverse residual stress is lower using austenitic filling metal, but longitudinal stress is much smaller using LTT filling metal. Longitudinal stress distribution for both LTT and austenitic filling metals is very high in the heat-affected zone, which is close to the yield stress of base metal. The LTT filling metal can not only guarantee the strength of welded joint for armor steel, but also reduce the welding distortion obviously, and the residual stress is also very low at the same time. The predicted temperature profiles and welding distortion are generally in good agreement with the experimental ones.

A novel modeling approach for multi-passes butt-welded plates

Numerical simulation of welding process in the industrial field requires flexibility, speed, and accuracy at the same time. The use of conventional 3D models in detailed simulations of multi-pass welds is time-consuming, and it often slows down the design phase of large welded structures. Shell elements are usually employed in the finite element (FE) simulation of large structures like vessels and pipes. Nevertheless, employing a simple shell model to simulate multi-pass welds would most likely produce inaccurate outcomes. This article introduces a new equivalent parametric modeling methodology for the simulation of longitudinal multi-pass welds on plane structures, such as plates and rectangular hollow sections. The proposed Weld Equivalent Model (WEM) is made with single and multi-layer shell, link and beam elements. It helps detect residual stress and local distortion that are typical of multi-pass welds. This method employs thermal transient and steady-state structural analyses. The WEM model is generated by an automatic subroutine acting on a pre-existing FE shell model. In addition to this, a case study is reported of multi-pass welding of two plates featuring a V-shaped groove. This innovative weld modeling technique shows remarkable results and helps shorten computational time up to ten times compared to classical 3D numerical models.

Application of analytical methods for determination of hardness distribution in welded joint made of S1100QL steel

The prediction of hardness distribution in the cross section of welded join made of S1100QL steel is performed in this study on the basis of analytical methods. Analytical CCT diagram and volume fraction of each phases of S1100QL steel as a function of cooling time t8/5 are determined. A numerical simulation of welding process is performed in ABAQUS. Thermal cycles and temperature field in welded joints are determined. Prediction of hardness distribution in the cross section of the joint is performed on the basis of obtained cooling times t8/5. Results of numerical simulations are compared with experimentally obtained results.

Numerical Simulation of Welding Process – Application in Buckling Analysis

Numerical simulations make the improvement of fabrication process and welding technology. Numerical simulations make the improvement of fabrication process and welding technology possible. Using finite element method the most important information about welded specimens can be determined such as deformed shape, residual stresses or even microstructural properties like phase proportions or hardness. The current study focuses on the modelling background of welding processes and the effects of different welding parameters on residual stresses and deformations. The paper focuses on heat sources, temperature dependent material properties and the development of a thermo-mechanical analysis. The virtually fabricated specimens are further analysed to investigate the stability behaviour.

Finite-Element Analysis of Heat Generation by Plasma in Welding Temperature Field of Stainless Steel

In this paper, the plasma arc welding is studied and stainless steel temperature field is gained in this process. The available heat source models, either planar one like Gaussian or body ones like double-ellipsoidal and rotary Gaussian modes, are unable to describe the keyhole PAW process accurately. Based on the configuration feature of keyhole PAW welds, a combined heat source model is proposed for the numerical analysis of temperature fields in keyhole PAW process. Numerical simulation of welding process in SIMPELC method and by ANSYS software for gaining the temperature field of stainless steel, the effect of parameter variation on temperature field and process optimization for different cases of plasma and shielding gases(Argon, Helium), are done.

Research and Application Status of Arc Welding Heat Source Model for T-Joint Numerical Simulation

During numerical simulation of welding process, the temperature field simulation is fundamental for simulating other issues of welding process, and establishing the heat source model is the most basic work for temperature filed simulation. Based on the analysis and induction of arc welding heat source model used in T-joint welding simulation, points out the existing problems and future development direction of heat source model for T-joint, provides a reference for further research and practical application.

Methodologies and experimental validations of welding process numerical simulation

The development of numerical codes for the simulation of metallurgical processes, such as welding, assumes a great importance in the industrial and research field. The prediction of residual stresses, deformations, phases proportion and temperature can be a fundamental step for a good planning of a welding operation. Due to the complexity of the problem, such numerical simulations require specialised tools and qualifications. The aim of this work is to summarise the methodologies currently used in the numerical simulation of welding process, with a particular attention paid to the strategies used to reduce the computational time. Some examples, mainly concerning high power source welding process will be described; numerical simulations, performed with the code SYSWELD and experimental results will be compared and discussed.

Residual Stress Correlation in Two Different Mitigation Techniques Using FEA

Many techniques were developed to control residual stress and distortion during welding process to minimizes their magnitude in the affected area. Due to complicity to find qualitative analysis for welding residual stress and distortion in real experiment work, the numerical simulation of welding process give a good solution to helpful the process and evaluated extensive analysis. In the present paper two different residual stress mitigation techniques moving cooling spot and moving heating spot were investigated in thin welded sheet structure using FEA. Thermo mechanical analysis and simulation of the processes were performed by ANSYS. The obtained results show different residual stresses behaviour developed during welding, the residual stress magnitude were minimized in both used techniques especially in trailing heat sink welding process. The out of plane distortion results show successfully eliminating of cambering distortion, it is also found that the effective elimination are based on the proper position parameters with respect to the welding heat source.

Sensitivity analysis of history dependent material mechanical models for numerical simulation of welding process

Yield stress of 6013-T6 aluminium alloy was tested on Gleeble 1500D thermal–mechanical system at predesigned temperatures during different typical thermal cycles, in order to accurately reflect the influence of weld thermal history on material properties. The typical thermal cycles were referred to the temperature field simulation results of real welding process. The changes of yield stress were obtained directly from the stress–strain curves generated by the tensile tests. The tests were more accurate than previous publications, where only the yield stresses at room temperature after thermal history were tested or calculated from microstructure evolution model. Experimental results showed that the changes of yield stress during the cooling stage of typical thermal cycles followed one set of curves. These yield stress–temperature curves were different from those during the heating stage. Temperature and temperature history dependent material model M2 and M3 were established based on the experimental results. M2 model was perfectly plastic model while work hardening effect was considered in M3 model. Compared with conventional temperature dependent material model M1, the distributions of longitudinal residual stress and strain obtained with temperature and temperature history dependent models fit better with published results. Yield stress of the material at the weld zone decreased a lot after having experienced weld thermal history and longitudinal compressive plastic strain at the weld zone recovered to some extent during the cooling stage in M2 and M3 models. These were the main causes for lower peak longitudinal residual tensile stress in M2 and M3 models.

A Numerical Simulation of Welding Process with Electrofusion Joint

A Numerical Simulation of Welding Process with Electrofusion Joint

溶接条件の最適化に関する研究 第３報 計算モデルによる溶接条件の推定と探索

In this paper, a feasibility study has been performed to determine if a computerized method by the numerical model of process could be used to estimate the optimal process parameter in arc welding.In the first part of this paper, a method of optimization of process parameters in arc welding has been discussed. The method is based on the numerical calculation of weld pool by a finite difference model, and a nonlinear optimization technique is applied to estimate the optimal process parameter in arc welding.In the second part of this paper, a system of on-line optimization has been developed on the basis of the above method, where the temperature in welding detected by infrared sensors is used to identify the numerical moedl. The developed system for TIG arc welding made it possible to optimize the process parameter in real time.Accordingly, it is concluded that the method based on the numerical simulation of welding process is a useful guide to the optimal process parameter in arc welding.