Simulation Of Friction Stir Welding Research Articles

Numerical Simulation of Friction Stir Welding of Dissimilar Al/Mg Alloys Using Coupled Level Set and Volume of Fluid Method.

The coupled level set and volume of fluid (CLSVOF) method is proposed to simulate the material distribution and physical properties during dissimilar aluminum/magnesium friction stir welding (FSW) process more accurately. Combined with a computational fluid dynamics model, the FSW process is numerically simulated and the heat transfer and material flow are analyzed. The results show that heat transfer and material flow have great influence on the Al/Mg bonding. In order to verify the accuracy of the model, the calculated results based on different methods are compared with the experimental results, and the Al/Mg interface simulated by the CLSVOF method is in better agreement with the experimental results. Finally, the material distribution and interface evolution near the tool at different times were studied based on the CLSVOF method.

Modeling and Simulation of Friction Stir Welding of Aluminum and Magnesium Alloys Using Finite Element Analysis

Modeling and Simulation of Friction Stir Welding of Aluminum and Magnesium Alloys Using Finite Element Analysis

Experimental Investigations and Finite Element Simulation of Friction Stir Welding of Various Aluminium Alloys AA2024 and AA2519

Abstract: In friction stir welding (FSW), a rotating spherical leg tool is forced to plunge into the plates to be welded and moved along their contact line. The tool penetrates into the work pieces. During this operation, frictional heat that’s generated by contact friction between the tool and work piece. The plasticized material is stirred by the tool and forced to “flow’’ to the side and the reverse of the tool advantage as the temperature cools down, a solid nonstop joint between the two plates is than formed. In this project work, DEFORM -3D is used to perform the finite element analysis and experimental investigation on the FSW in order to predict residual stresses, temperatures, normal stresses and distortion of the welded structures, that are induced during FSW of the given airframe structures made up of AA 2024 and AA 2519. The weld quality characteristics like hardness, and tensile strength properties of the joints are analyzed

Material Defects in Friction Stir Welding through Thermo–Mechanical Simulation: Dissimilar Materials with Tool Wear Consideration

Despite the remarkable capabilities of friction stir welding (FSW) in joining dissimilar materials, the numerical simulation of FSW is predominantly limited to the joining of similar materials. The material mixing and defects' prediction in FSW of dissimilar materials through numerical simulation have not been thoroughly studied. The role of progressive tool wear is another aspect of practical importance that has not received due consideration in numerical simulation. As such, we contribute to the body of knowledge with a numerical study of FSW of dissimilar materials in the context of defect prediction and tool wear. We numerically simulated material mixing and defects (surface and subsurface tunnel, exit hole, and flash formation) using a coupled Eulerian-Lagrangian approach. The model predictions are validated with the experimental results on FSW of the candidate pair AA6061 and AZ31B. The influence of tool wear on tool dimensions is experimentally investigated for several sets of tool rotations and traverse speeds and incorporated in the numerical simulation to predict the weld defects. The developed model successfully predicted subsurface tunnel defects, surface tunnels, excessive flash formations, and exit holes with a maximum deviation of 1.2 mm. The simulation revealed the substantial impact of the plate position, on either the advancing or retreating side, on the defect formation; for instance, when AZ31B was placed on the AS, the surface tunnel reached about 50% of the workpiece thickness. The numerical model successfully captured defect formation due to the wear-induced changes in tool dimensions, e.g., the pin length decreased up to 30% after welding at higher tool rotations and traverse speeds, leading to surface tunnel defects.

Determination of self-adaptive slip rate at tool/workpiece interface in numerical model of friction stir welding

As a key parameter affecting the heat generation and the interface material velocity, the interface slip rate is a prerequisite for numerical simulation of friction stir welding of lightweight materials. The contact state on the tool/workpiece interface is related to friction stress and material yield strength, and a new calculation method of the self-adaptive interface slip rate was established. The interface velocity of material flow, heat generation due to friction and plastic deformation near the tool and temperature distribution were analyzed quantitatively. The calculated self-adaptive interface slip rate has a wider range than the previous used one, from a sticking dominant for the material near the inner part of the shoulder to a sliding dominant for the material near the edge of the shoulder. With application of this improved method determining the slip rate, the material flow velocity at the tool/workpiece interface is roughly in a "M" shape, which first increases and then decreases as the radial distance rises, and the maximum interfacial material velocity no longer appears at the shoulder edge. The experiments were made to validate the method. The slip rate distribution at tool/workpiece interface in (a) Previous mode; (b) Improved mode.

The Influence of the Tool Tilt Angle on the Heat Generation and the Material Behavior in Friction Stir Welding (FSW)

To improve the accuracy of numerical simulation of friction stir welding (FSW) process, the tool tilt angle must be considered as a significant parameter. In this study, specific considerations for mechanical boundary conditions in Eulerian domain is employed to investigate the tool tilt angle influence on the thermomechanical behavior in FSW. Aluminum 6061-T6 with a thickness of 6 mm under a rotational speed of 800 RPM, a transverse speed of 120 mm/min, and a plunging depth of 0.1 mm were employed for the simulations. Results showed an almost symmetric temperature profile predicted by the model without considering the tool tilt angle, while after incorporating the tool tilt angle, the peak temperature point is moved to the tool backside (around 400 °C), resulting in better material bonding, enhancing the weld joint quality. Without accounting for the tool tilt angle, the highest temperature of 389 °C is observed, while with the tilt angle the maximum temperature of 413 °C is achieved. The temperature variations at different points of the leading (around 360 °C) and the trailing sides (around 400 °C) of the welding tool were measured. It was observed that, after considering the tilt angle, as the tool moves, a smooth and quick increase for the temperature at the tool trailing side is achieved. This smooth and quick increasing of the temperature at the trailing side results in reducing the possibility of the formation of defects, cracks, and voids. Finally, comparisons showed that the model computational time is acceptable, and using Eulerian formulation leads to achieving a remarkable accuracy.

Reversible inter-particle bonding in SPH for improved simulation of friction stir welding

Friction stir welding (FSW) is a complex joining process which is governed by multiple intertwined physical phenomena. Besides friction, inelastic heat generation, and heat conduction, it involves high plastic deformations, resulting in a need for a numerical method being able to handle all these. Such a scheme is smoothed particle hydrodynamics (SPH), which is a mesh-free computational technique. Absence of a fixed mesh results in the ability of the method to deal with another challenge of friction stir welding, a coalescence of initially separate workpieces into one due to bonding mechanisms. The background of this phenomenon is a transition from contact between two pieces to one continuum due to enormous changes in several material condition, such as temperature, pressure, strain, and strain rate. This work deals with a new development related to bonding, which will provide deeper understanding about the physical weld formation during FSW. The SPH framework must be extended to consider this bonding mechanism. This involves the bonding criterion definition, the interaction type change, and the SPH–SPH contact formulation. Then, the implementation is tested for two different examples, a compression test and FSW.

Entire-Process Simulation of Friction Stir Welding — Part 2: Implementation of Neural Networks

To further understand the structure-parameter-property relationships of friction stir welded aluminum alloy joints, a nested neural network was proposed to map the macro- and microstructural response. The uncoupled effect of each primitive parameter on the joint performance was depicted. Reducing heat input and keeping an adequate load-bearing area of the welding nugget zone were proven to be the sufficient and necessary conditions to obtain high load-bearing performance. The entire-process simulation strategy showed great potential for prediction and optimization of the macro- and microstructural response of complex and large components.

Entire Process Simulation of Friction Stir Welding — Part 1: Experiments and Simulation

Understanding structure-parameter-property relationships in friction stir welding of aluminum alloys is a challenge despite its wide application in load-bearing components. In this paper, we propose a combined strategy for mapping the macro- and microstructural responses of these joints. A combined model based on experiment validation was adopted for the prediction of tensile strength. This included the computational fluid dynamics model, precipitation evolution model, dynamic recrystallization and recovery model, and computational solid mechanics model. The comparison between the experimental results and the combined model proved the rationality and accuracy of this numerical model.

On the Framework of Numerical Modeling and Simulation of Friction Stir Welding: A Critical Review

On the Framework of Numerical Modeling and Simulation of Friction Stir Welding: A Critical Review

Numerical investigation and prediction of grain size in different friction stir welding areas of AA6061 aluminum alloy

Friction stir welding is a solid-state bonding technique based on two factors, a pressure greater than the material yield stress and large plastic deformation. The final joint between parts takes place in different welding geometries by using these two factors. The grain sizes in the weld areas are influenced by recovery, recrystallization, and grain growth. In the current research, using an analytical-numerical method based on finite element simulation of friction stir welding of AA6061-T6 alloy, the grain sizes in various welded areas have been predicted. The finite element simulation has been performed based on the coupled Eulerian-Lagrangian approach using ABAQUS software and the results have been verified by experiments. The predicted results were in good agreement with the experimental results. Due to the concentration of heat and plastic flow in the central region of the weld, the stirring region had the most microstructural changes and the grain size in this region decreased more sharply than other different areas of the weld. As the rotational welding speed increases, recrystallization phenomena in the central weld area increases. With increasing the translational welding speed, grain size increased in different welding areas. This increase occurred more severely in the central area of the welded joint.

Status Quo of Numerical Simulation of Friction Stir Welding After Deformation under Big Data Analysis

Friction stir spot welding is a new type of connection technology developed on the basis of the friction stir welding process. It uses a high-speed rotating stirring head to generate heat by friction with the plate to make the welding material reach a thermoplastic softened state, forming a lap joint similar to resistance spot welding. The purpose of this article is to analyze and analyze the current situation of numerical simulation of friction stir welding after deformation under big data analysis. Algorithm mining commonly used for analysis of big data. This paper proposes to use the classic algorithm FP-growth algorithm. The FP-growth algorithm has the widest application range. It compresses the transaction database into a FP tree for processing. It also uses the Apriori algorithm, which eliminates the need to generate candidate frequent itemsets, which improves the efficiency of use. In addition, this article uses data mining technology and data fusion technology commonly used in big data analysis, and their application strengthens the analysis of the current situation of numerical simulation after friction stir welding deformation under big data analysis. Experimental research shows that the dynamic FSSW technology used in this paper simulates the numerical change after friction stir welding deformation, and the simulated data effect is better than the traditional GPC algorithm by about 20%.

Flow Stress of 6061 Aluminum Alloy at Typical Temperatures during Friction Stir Welding Based on Hot Compression Tests

The purpose of this paper is to report quantitative data and models for the flow stress for the computer simulation of friction stir welding (FSW). In this paper, the flow stresses of the commercial 6061 aluminum alloy at the typical temperatures in FSW are investigated quantitatively by using hot compression tests. The typical temperatures during FSW are determined by reviewing the literature data. The measured data of flow stress, strain rate and temperature during hot compression tests are fitted to a Sellars–Tegart equation. An artificial neural network is trained to implement an accurate model for predicting the flow stress as a function of temperature and strain rate. Two models, i.e., the Sellars–Tegart equation and artificial neural network, for predicting the flow stress are compared. It is found that the root-mean-squared error (RMSE) between the measured and the predicted values are found to be 3.43 MPa for the model based on the Sellars–Tegart equation and 1.68 MPa for the model based on an artificial neural network. It is indicated that the artificial neural network has better flexibility than the Sellars–Tegart equation in predicting the flow stress at typical temperatures during FSW.

Modal Analysis of FSW Plate Considering the Residual Stresses Effect

In this paper, a modal analysis of the FSW plate is performed to identify the modal parameters such as: frequencies and eigenvectors. A finite element simulation is carried out by using ANSYS commercial software. The brick element called SOLID70 is used to model the weld joint in order to represent the welded structure with good precision thus determined the residual stresses in the plate. The modal analysis is use to extracting the vibration behavior of the FSW plate made of AA6061-T6 aluminum alloy with consideration the residual stresses effect on the modal parameters of the plate. The numerical results found in the friction stir welding simulation are compared by a reference plate to analyze the influence of residual stresses on the fundamental frequencies and modal deformations. The study concluded that the presence of residual stresses induced by the FSW process influences the modal behavior of the welded plates.

Simulation of Friction Stir Welding Process Temperature Distribution on AA6061-T6 Material Static Position

Friction Stir Welding (FSW) is a welding method that utilizes heat from friction between two objects, namely the tool and the material being welded. To melt the material with heat required about 80% of the melting temperature of the material. In the FSW simulation to predict the temperature distribution on the AA6061-T6 plate measuring 200mm long, 100mm wide, 6mm thick using various pin shapes, namely, cylinder, taper cylinder, hexagonal, and taper square showing at a distance of 140mm with a hexagonal pin the temperature value is 481° C where the temperature is higher than the other pins when measured from the same distance. When using a taper square pin a distance of 190mm the temperature value is 468°C which is the lowest temperature when compared to using other pins when measured from the same distance. The results of the calculation of the heat transfer rate show that the largest energy is 7110 watts which is located at position 1 and close to the FSW tool area. Energy will decrease further if the measured position is further away from the FSW tool position.

Stress Field Simulation of Friction Stir Welding and Laser Peening Composite Process

Stress Field Simulation of Friction Stir Welding and Laser Peening Composite Process

A physically based material model for the simulation of friction stir welding

Abstract A physically based material model, taking into account the interdependence of material microstructure and yield strength, is presented for an Al 5182 series aluminum alloy for the simulation of friction stir welding using continuum mechanics approaches. A microstructure evolution equation considering dislocation density and grain size is used in conjunction with a description of yield stress. In order to fit experimental stress-strain curves, obtained from compression tests at various strain rates and temperatures, phenomenological relationships are developed for some of the model parameters. The material model is implemented in smoothed particle hydrodynamic research code as well as in the commercial finite element code Abaqus. Simulations for various strain rates and temperatures were performed and compared with experimental results as well as between the two discretization methods in order to verify the material model and the implementation. Simulations provide not only an accurate approximation of stress based on temperature, strain rate, and strain but also an improved insight into the microstructural evolution of the material.

A physically based material model for the simulation of friction stir welding

AbstractA physically based material model, taking into account the interdependence of material microstructure and yield strength, is presented for an Al 5182 series aluminum alloy for the simulation of friction stir welding using continuum mechanics approaches. A microstructure evolution equation considering dislocation density and grain size is used in conjunction with a description of yield stress. In order to fit experimental stress-strain curves, obtained from compression tests at various strain rates and temperatures, phenomenological relationships are developed for some of the model parameters. The material model is implemented in smoothed particle hydrodynamic research code as well as in the commercial finite element code Abaqus. Simulations for various strain rates and temperatures were performed and compared with experimental results as well as between the two discretization methods in order to verify the material model and the implementation. Simulations provide not only an accurate approximation of stress based on temperature, strain rate, and strain but also an improved insight into the microstructural evolution of the material.

Modelling and Simulation of Friction Stir Welding and Under Water Friction Stir Welding of Al6063 Alloy

Friction stir welding (FSW) is a solid-state welding process that is gaining importance in recent times due to better control of microstructure. In the present work, a thermo-mechanical model is developed for FSW and under water friction stir welding (UFSW) of AA 6063-T6. Temperature dependent viscosity is considered as thermo physical property along with constant values of thermal conductivity and specific heat. Fine mesh is used for complex parts of tool to obtain good results. Rotational speed of tool, feed rate and plunge pressure are taken as influencing parameters for study. Partial stick-slip boundary condition is taken between the tool and work piece interfaces. Experiments were carried out for validation of model. The results of thermal and material flow histories are extracted. Results shows the significant differences in peak temperature of FSW and UFSW along with reduction in heat affected zone in UFSW whereas results of material flow velocity underlined the differences between the FSW and UFSW in term of peak values of stir velocities with the change in influencing parameters.

Investigation of Mechanical and Numerical Properties of Friction Stir Welding (FSW) for 3003 - H14 Aluminum Alloys

In this paper, friction stir welding (FSW) has been focused on 3003 - H14Al alloy (AA).The welded specimens have been organized. Under dissimilar rotational rates of 1200, 1400 and 1600 RPM with feeding rate of welding 30 mm/min, mechanical features of joints like tensile strength and Micro-hardness have been investigated. In relation to measured fallouts, the machine-driven features of joints have been intensely influenced by dint of welding limitation. The finest con sequences of gained welding under 30 mm/min and 1400 RPM for welding velocity and rotating rate respectively. Accordingly, the efficiency gets 84% with respect to ultimate tensile strength (UTS) of parental metal. For 3003 - H14-W Aluminum alloy, this study has established the finite element simulation of FSW. Numerical simulations to identify the association of those factors with peak temperature have generated the investigations of specific heat, thermal conductivity and density. Simulation model has been verified with investigational consequences. The simulated consequences have agree with the experimentation consequences.