Showing papers on "Material flow published in 2021"

Analysis of friction stir welding tool offset on the bonding and properties of al–mg–si alloy t-joints

Abstract: Research on T-configuration aluminum constructions effectively decreases fuel consumption, increases strength, and develops aerial structures. In this research, the effects of friction stir welding (FSW) tool offset (TO) on Al–Mg–Si alloy mixing and bonding in T-configurations is studied. The process is simulated by the computational fluid dynamic (CFD) technique to better understand the material mixing flow and the bonding between the skin and flange during FSW. According to the results, the best material flow can be only achieved at an appropriate TO. The appropriate TO generates enough material to fill the joint line and results in formation of the highest participation of the flange in the stir zone (SZ) area. The results show that, in the T-configuration, FSW joints provide raw materials from the retreating side (RS) of the flange that play a primary role in producing a sound mixing flow. The selected parameters were related to the geometric limitations of the raw sheets considered in this study. The failure point of all tensile samples was located on the flange. Surface tunneling is the primary defect in these joints, which is produced at high TOs. Among the analyzed cases, the most robust joint was made at +0.2 mm TO on the advancing side (AS), resulting in more than 60% strength of the base aluminum alloy being retained.

Numerical and experimental analysis of resin-flow, heat-transfer, and cure in a resin-injection pultrusion process

Abstract: This paper concerns non-isothermal flow in a thermoset resin-injection pultrusion process. Supported by temperature measurements from an industrial pultrusion line and a material characterisation study (curing kinetics, chemorheology, and permeability), the material flow was analysed for the manufacture of a thick glass-fibre profile saturated with a pultrusion-specific polyurethane resin. A central finding is that the heating configuration, together with the strongly convective flow near inlets resulted in phase transitions that were both concave and convex-shaped. This is different from existing literature that commonly describes curing being initiated from die-walls, resulting in the concave phase-transitions.

Analysis of the impact of covid-19 on the coupling of the material flow and capital flow in a closed-loop supply chain

Abstract: The complex and changeable external social and economic environment has a significant impact on the sustainable development of the closed-loop supply chain In particular, the occurrence of uncertain emergencies increases the risk of interruption of the closed-loop supply chain, making it insufficient to analyze its complex changes from the perspective of material flow alone Based on this analysis, the paper constructs a closed-loop supply chain material flow and capital flow coupling system composed of manufacturers, sellers and recyclers to explore the impact of material flow sudden interruption on the closed-loop supply chain system when an uncertain emergency occurs In this paper, based on the closed-loop supply chain system coupled with logistics and capital flow, a system dynamics simulation model was established by using Vensim simulation software to analyze the impact of COVID-19 epidemic on manufacturers, sellers and recyclers under five scenarios The results show that when COVID-19 outbreaks occur, the material flow of each main enterprise in the closed-loop supply chain is more easily influenced than the capital flow At the same time, it can be found that the recyclers in the main enterprises of the closed-loop supply chain are more easily influenced by the material flow The model constructed in this paper has applicability and can be used for related studies of closed-loop supply chain under other emergencies, but the scene design should be carried out according to the characteristics of emergencies themselves © 2021 Production Engineering Institute All rights reserved

Microstructure and texture correlation of secondary heating assisted dissimilar friction stir welds of aluminum alloys

Abstract: Present work aims to study the influence of secondary heating on material behavior during the friction stir welding (FSW) and examine it through the texture analysis. In the present context, the secondary heating pertains to the additional heat provided using a gas torch other than the heat primarily produced due to the process itself. Stop tool action technique is used to appraise the material flow around the pin. The material flow and evolution of textures during the process is studied by employing electron backscatter diffraction analysis. For analysis, the transverse sections of dissimilar FSW joints of AA6061-AA7075 and AA7075-AA2014 prepared with and without the application of secondary heating keeping the tool pin embedded in the joint are used. The basic assertions on strain rate based upon texture analysis and grain boundary engineering are used to explain the nature of material behavior during the process. The misorientation angle distribution is observed to shift towards random distribution for severe plastic deformation and additional heat supplied. Texture analysis reveals dominance of B / B ‾ shear texture with sufficient C component in joints supplied with additional heating. For AA7075-AA2014 (without secondary heating) strong α-fiber is observed in the texture orientation distribution function plots. An equation is established to estimate the material volume flow around the pin in one revolution. The optical micrographs of welded joints prepared with and without use of secondary heating are compared to visualize the increase in material flow volume. The hardness of the joints obtained tend to decrease along the weld section on application of additional heat due to the dissolution of precipitates.

Combining the worlds of energy systems and material flow analysis: a review

Abstract: Recent studies focusing on greenhouse gas emission reduction strategies indicate that material recycling has a significant impact on energy consumption and greenhouse gas emissions. The question arises how these effects can be quantified. Material recycling is not at all or insufficiently considered in energy system models, which are used today to derive climate gas mitigation strategies. To better assess and quantify the effects one option would be to couple energy system models and material flow models. The barriers and challenges of a successful coupling are addressed in this article. The greatest obstacles are diverging temporal horizons, the mismatching of system boundaries, data quality and availability, and the underrepresentation of industrial processes. A coupled model would enable access to more robust and significant results, a response to a greater variety of research questions and useful analyses. Further to this, collaborative models developed jointly by the energy system and material analysis communities are required for more cohesive and interdisciplinary assessments.

Effect of flow behavior and process-induced variations on shape stability of 3D printed elements – A review

Abstract: Successful implementation of extrusion-based 3D printing (3DP) of concrete requires knowledge of material flow behavior during pumping and extrusion and its influence on shape stability of printed elements. Limited emphasis exists on flow behavior and process-induced variations in material properties (rheology and composition) during printing. This paper delineates the effect of flow behavior and process-induced variations on shape stability. A comprehensive review of material flow behavior during pumping and extrusion is discussed, and its influence on shape stability of 3DP elements is highlighted. The extent of shearing in print material is shown to govern process-induced variations during pumping and extrusion. During extrusion, the degree of filtration and consolidation plays a significant role on shape stability. Accurate assessment of process-induced changes in material properties is required to ensure steady and continuous flow of material during 3DP and secure proper shape stability of printed elements.

In-depth understanding of material flow behavior and refinement mechanism during bobbin tool friction stir welding

Abstract: Bobbin tool friction stir welding (BT-FSW) is a promising solid-state welding process for fabricating closed or hollow profiles due to its self-supporting nature, which is achieved using a combined tool consisting of two shoulders and a penetrating pin, releasing the backing plate. The joint reliability is mainly affected by its macro-/micro-features including geometric defects and non-uniform grains. However, the underlying thermo-physical process has not been fully understood to clarify how the defects form and grains evolve during welding and how to control them. In this paper, a 3D thermo-mechanically coupled Eulerian-Lagrangian model was developed to analyze the material flow behavior and help understand the defect forming mechanism and recrystallization behavior during BT-FSW of aluminum alloy, wherein tracing particles were specially embedded. The calculated results revealed a complex material migration in the domain driven by the rotating tool. The flow behavior in horizontal/vertical directions at local regions was asynchronous, and eventually converged on the advancing side (AS) to normally form a sound joint, where the combined effects of shearing and squeezing of the material flow throughout thickness affected the morphology of S-line defect. In addition, the non-uniform thermo-mechanical cycling caused an abrupt change in grain structure near the TMAZ/SZ-AS transition region due to the combined continuous and discontinuous dynamic recrystallization, and geometrical effect of strain. The final joint failure was the result of competition between the two softening regions, S-line defect and TMAZ/SZ-AS. These can be applied for further fundamental investigation of parameter optimization or welding structure design, and promote the exploration of post-processing methods to improve the joint performance.

Plug Regime Flow Velocity Measurement Problem Based on Correlability Notion and Twin Plane Electrical Capacitance Tomography: Use Case.

Abstract: In this paper, the authors present the flow velocity measurement based on twin plane sensor electrical capacitance tomography and the cross-correlation method. It is shown that such a technique has a significant restriction for its use, particularly for the plug regime of a flow. The major issue is with the irregular regime of the flow when portions of propagated material appear in different time moments. Thus, the requirement of correlability of analyzed input signal patterns should be met. Therefore, the checking of the correlability should be considered by such a technique. The article presents a study of the efficiency of the original algorithm of automatic extraction of the suitable signal patterns which has been recently proposed, to calculate flow velocity. The obtained results allow for choosing in practice the required parameters of the algorithm to correct the extraction of signal patterns in a proper and accurate way. Various examples of the application of the discussed algorithm were presented, along with the analysis of the influence of the parameters used on the quality of plugs identification and determination of material flow.

Effect of friction stir welding parameters on the material flow, mechanical properties and corrosion behavior of dissimilar AA5083-AA6061 joints:

Abstract: Material flow has a significant impact on the joint properties and is one of the most challenging aspects to be understood in dissimilar friction stir welding. The present study emphasizes the role...

Formation of the periodic material flow behaviour in friction stir welding

Abstract: A two-dimensional computational fluid dynamics model is established to verify the correlation between periodic material flow and tool eccentricity during friction stir welding (FSW) process. In the...

Probing the Mechanism of Friction Stir Welding with ALE Based Finite Element Simulations and Its Application to Strength Prediction of Welded Aluminum

Abstract: In this study, a simulation-based examination on the deformation mechanism in the friction stir welding (FSW) process is conducted, which may not be efficiently feasible by experiment due to severe deformation and rotation of material flow near a tool pin. To overcome the severity of distortion of plastically deforming finite element meshes in the Lagrange formulation, and an over-simplified elastic-plasticity constitutive law and contact assumption in the Eulerian formulation, the arbitrary Lagrangian–Eulerian (ALE) formulation is employed for the finite element simulations. Superior accuracy in predicting the temperature profiles and distributions of the friction stir welded aluminum alloy workpiece could be obtained compared to the results of Eulerian based simulations. In particular, the ALE based simulations could predict the sharper gradient of temperature decrease as the distance from the welding zone increases, while the Eulerian based model gives more uniform profiles. The second objective of the study is to investigate the coupling of simulation-based temperature histories into the strength prediction model, which is formulated on the basis of precipitation kinetics and precipitate-dislocation interaction. The calculated yield strength distribution is also in better agreement with experiment than that by the Eulerian based model. Finally, the mechanism of the FSW process is studied by thoroughly examining the frictional and material flow behavior of the aluminum alloy in the welded zone. It is suggested that the initially high rate of temperature increase is attributed to frictional heat due to slipping of material on the tool surface, and the subsequent saturated temperature is the result of sequential repetitive activations of the sticking and slipping modes of the softened material. The sticking mode is the main source of plastically dissipated heat by the large plastic deformation around the rotating tool pin. The present integrated finite element simulation and microstructure-based strength prediction model may provide an efficient tool for the design of the FSW process.

Visualising food traceability systems: A novel system architecture for mapping material and information flow

Abstract: Background Traceability of food products, ingredients and associated operations are important requirements for improving food safety and consumer confidence. Food traceability systems (FTSs) often suffer from inefficiency in either material or information flow within an enterprise or between supply chain partners. Modelling of system architecture is a visualisation approach that allows multiple parties to collaborate in a system design process, identify its inefficiencies and propose improvements. However, there is little academic research on the ability to use a standard visualisation tool that supports collaborative design and considers both material and information flow for a given food traceability system. Scope & approach The aim of this research is to propose a new visualisation approach that allows supply chain operators to collaborate effectively in the design process of FTSs capable of maintaining streamlined information flow, minimising information loss, and improving supply chain performance. Key findings & conclusion Food traceability systems are complex, encompassing processes, material flow, information flow, techniques, infrastructure, people and control strategies. Screening of literature demonstrates that model-based system engineering (MBSE) offers a sound way for visualisation of such complex systems. However, in the food traceability literature, an MBSE-based standardised traceability system modelling approach is absent. This study makes a strong contribution to existing literature by proposing a novel, material and information flow modelling technique (MIFMT), to visualise FTS architecture. MIFMT can support common understanding and iterative implementation of effective FTSs that contextualise food supply chains at multiple levels and provides opportunity to identify points at where inefficiencies can occur so that actions can be taken to mitigate them.

Finite Element and Finite Volume Modelling of Friction Drilling HSLA Steel under Experimental Comparison.

Abstract: Friction drilling is a widely used process to produce bushings in sheet materials, which are processed further by thread forming to create a connection port. Previous studies focused on the process parameters and did not pay detailed attention to the material flow of the bushing. In order to describe the material behaviour during a friction drilling process realistically, a detailed material characterisation was carried out. Temperature, strain rate, and rolling direction dependent tensile tests were performed. The results were used to parametrise the Johnson–Cook hardening and failure model. With the material data, numerical models of the friction drilling were created using the finite element method in 3D as well as 2D, and the finite volume method in 3D. Furthermore, friction drilling tests were carried out and analysed. The experimental results were compared with the numerical findings to evaluate which modelling method could describe the friction drilling process best. Highest imaging quality to reality was shown by the finite volume method in comparison to the experiments regarding the material flow and the geometry of the bushing.

Prediction and validation of temperature distribution and material flow during refill friction stir spot welding of AZ91D magnesium alloy

Abstract: Temperature distribution and material flow behaviours during refill friction stir spot welding (RFSSW) of AZ91D magnesium alloy were studied by a combination of numerical modelling and experimentat...

On the steady-state workpiece flow mechanism and force prediction considering piled-up effect and dead metal zone formation

Abstract: The manufacturing of miniaturized components is indispensable in modern industries, where the uncut chip thickness (UCT) inevitably falls into a comparable magnitude with the tool edge radius. Under such circumstances, the ploughing phenomenon between workpiece and tool becomes predominant, followed by the notable formation of dead metal zone (DMZ) and piled-up chip. Although extensive models have been developed, the critical material flow status in such microscale is still confusing and controversial. In this study, a novel material separation model is proposed for the demonstration of workpiece flow mechanism around the tool edge radius. First, four critical positions of workpiece material separation are determined, including three points characterizing the DMZ pattern and one inside considered as stagnation point. The normal and shear stresses as well as friction factors along the entire contact region are clarified based on slip-line theory. It is found that the friction coefficient varies symmetrically about the stagnation point inside DMZ and remains constant for the rest. Then, an analytical force prediction model is developed with Johnson-Cook constitutive model, involving calibrated functions of chip-tool contact length and cutting temperature. The assumed tribology condition and morphologies of material separation including DMZ are clearly observed and verified through various finite element (FE) simulations. Finally, comparisons of cutting forces from cutting experiments and predicted results are adopted for the validation of the predictive model. (Less)

Effects of different cooling conditions on friction stir processing of A356 alloy: Numerical modeling and experiment:

Abstract: In the present work, the effects of in-process cooling are investigated on the material flow, temperature distribution, axial force, wear resistance, and microstructural and mechanical properties o...

Material flow behavior and microstructural evolution during refill friction stir spot welding of alclad 2A12-T4 aluminum alloy

Abstract: In this study, we used the stop-action technique to experimentally investigate the material flow and microstructural evolution of al-clad 2A12-T4 aluminum alloy during refill friction stir spot welding. There are two material flow components, i.e., the inward- or outward-directed spiral flow on the horizontal plane and the upward- or downward-directed flow on the vertical plane. In the plunge stage, the flow of plasticized metal into the cavity is similar to that of a stack, whereby the upper layer is pushed upward by the lower layer. In the refill stage, this is process reversed. As such, there is no obvious vertical plasticized metal flow between adjacent layers. Welding leads to the coarsening of S (Al2CuMg) in the thermo-mechanically affected zone and the diminishing of S in the stir zone. Continuous dynamic recrystallization results in the formation of fine equiaxed grains in the stir zone, but this process becomes difficult in the thermo-mechanically affected zone due to the lower deformation rate and the pinning action of S precipitates on the dislocations and sub-grain boundaries, which leads to a high fraction of low-angle grain boundaries in this zone.