Showing papers on "Material flow published in 2016"
TL;DR: In this article, a deep understanding of hot deformation behavior of a material plays a crucial role in determining process parameters and designing extrusion dies during the extrusion process of the aluminum alloy profiles.
94 citations
TL;DR: In this article, a decision model for sustainable design of biomass-based renewable energy supply chains and district heating systems with thermal energy storages was developed, which combines cost and service level objectives and accounts for biomass supply, material flow, capacity, demand and technical constraints.
83 citations
TL;DR: In this article, a new welding tool/work piece contact model is proposed to simulate material flow near the FSW tool, and the material around the tool flows under the driving force of friction non-uniformly distributed on the interface.
79 citations
TL;DR: In this paper, a 3D finite element based phenomenological model is developed to study various aspects of P-FSW between aluminum and copper, and a dedicated heat generation model at various contact conditions between tool and workpiece is used for the simulation.
61 citations
TL;DR: In this article, the probe route and the material flow around the keyhole during weld termination were tracked and used to determine the probe position just prior to weld termination, which enables analysis of in-situ microstructure distribution and the nature of material flow during friction stir welding.
53 citations
Book•
27 Jul 2016
TL;DR: In this article, the authors re-designed the material flow in a Global Manufacturing Network and presented a case study to evaluate the impact of this rewording on the performance of the network.
Abstract: Basics of Supply Chain and Operations Management.- Examples from Different Industries, Services and Continents.- Processes, Systems, and Models.- Operations and Supply Chain Strategy.- Sourcing Strategy.- Production Strategy.- Facility Location Planning and Network Design.- Distribution and Transportation Network Design.- Factory Planning and Process Design.- Layout Planning.- Demand Forecasting.- Production and Material Requirements Planning.- Inventory Management.- Routing and Scheduling.- Supply Chain Risk Management and Resiliance.- Digital Supply Chain, Smart Operations and Industry.- Pricing and Revenue-Oriented Capacity Allocation.- Appendix:Case-Study:Re-designing the Material Flow in a Global Manufacturing Network.
51 citations
TL;DR: The new "Dynamic Probabilistic Material Flow Analysis (DPMFA)" method, combining dynamic material flow modeling with probabilistic modeling, is presented in this paper and is implemented as a simulation framework in Python to support experts from different domains in the development of their application models.
Abstract: Material flow modeling constitutes an important approach to predicting and understanding the flows of materials through the anthroposphere into the environment. The new "Dynamic Probabilistic Material Flow Analysis (DPMFA)" method, combining dynamic material flow modeling with probabilistic modeling, is presented in this paper. Material transfers that lead to particular environmental stocks are represented as systems of mass-balanced flows. The time-dynamic behavior of the system is calculated by adding up the flows over several consecutive periods, considering changes in the inflow to the system and intermediate delays in local stocks. Incomplete parameter knowledge is represented and propagated using Bayesian modeling. The method is implemented as a simulation framework in Python to support experts from different domains in the development of their application models. After the introduction of the method and its implementation, a case study is presented in which the framework is applied to predict the environmental concentrations of carbon nanotubes in Switzerland. Presentation of a probabilistic modeling method for representing dynamic mass flows.Implementation as simulation framework.Case study: Exposure modeling of carbon nanotubes for Switzerland.
49 citations
TL;DR: In this paper, a conceptual balanced-flow model and a plastic material flow model were used to describe the material flow behavior, and the origin of the downward material flow in the advancing side was discussed.
Abstract: Material-flow behavior during friction-stir welding of 6082-T6 aluminum alloy has been visualized by marker insert technique. Four stacked layers were evolved in welding nugget zone (WNZ) in the transverse section. The material-flow behavior in vertical direction was detected by observing the distribution of Cu foil fragments and Al-Cu intermetallic compounds. The downward and upward flows encounter each other at the advancing side in the material depositing process, changing the morphology of WNZ. A conceptual balanced-flow model and a plastic material-flow model were used to describe the material-flow behavior, and the origin of the downward material flow in the advancing side was discussed. The excess-material flow derived by the welding tool due to the existence of the tilt angle is crucial to the weld formation.
49 citations
TL;DR: The IO-MFN approach has the following advantages: it helps to uncover the network of material flows in the manufacturing stage in the life cycle of metals, and provides a method that may be less time-consuming but more complete and accurate in estimating new scrap generation, process loss, domestic final demand, and trade of final products of metals.
Abstract: Based on the combination of the U.S. economic input-output table and the stocks and flows framework for characterizing anthropogenic metal cycles, this study presents a methodology for building material flow networks of bulk metals in the U.S. economy and applies it to aluminum. The results, which we term the Input–Output Material Flow Networks (IO-MFNs), achieve a complete picture of aluminum flow in the entire U.S. economy and for any chosen industrial sector (illustrated for the Automobile Manufacturing sector). The results are compared with information from our former study on U.S. aluminum stocks and flows to demonstrate the robustness and value of this new methodology. We find that the IO-MFN approach has the following advantages: (1) it helps to uncover the network of material flows in the manufacturing stage in the life cycle of metals; (2) it provides a method that may be less time-consuming but more complete and accurate in estimating new scrap generation, process loss, domestic final demand, an...
48 citations
TL;DR: The main aim of this paper is the proposal of a layout reconfiguration and a technological solution for the parts feeding system of the industrial plant analysed in order to reduce the production lead times.
Abstract: The ability to realize customized products, in particular for engineering-to-order companies, is a key factor in order to be competitive in modern market without incurring any additional cost and respecting customer lead time. In this ever-changing environment the layout optimization is a fundamental issue requirement, hence the development of a virtual layout, according to the Digital Factory concepts, can be very useful to identify and to solve potential problems during the planning phase, before realize it. The main aim of this paper is represented by the proposal of a layout reconfiguration and a technological solution for the parts feeding system of the industrial plant analysed in order to reduce the production lead times. In the first phase, an overview of the Digital Factory applications is provided. In the second phase, after data analysis in an Italian manufacturing company, a simulation model has been designed and tested using Simio simulation software. Simulations results concerning production and queue times obtained from different orders have been compared with actual configuration data. Research results indicate that the surveyed company has had an improvement in terms of reduction of waiting times and increase of customers satisfaction due to total production lead time reduction. (Received in May 2015, accepted in November 2015. This paper was with the authors 5 months for 1 revision.)
41 citations
TL;DR: A robust method to reduce the likelihood of delays in material flow by representing the system of suppliers within a supply chain as a fault-tree and proactively determining the optimum mitigation strategy for the portfolio is presented.
TL;DR: Within the present study different methods to adapt the surfaces are presented and investigated with respect to their tribological effectiveness in SBMF, and the potential of surface modifications to improve S BMF processes is shown.
Abstract: Sheet-bulk metal forming (SBMF) is characterized by successive and/or simultaneous occurrence of quite different load conditions regarding stress and strain states. These conditions significantly influence the material flow and thus the geometrical accuracy of the components. To improve the product quality a control of the material flow is required. An appropriate approach is given by locally adapted tribological conditions due to surface modifications of tool and workpiece, so-called tailored surfaces. Within the present study different methods to adapt the surfaces are presented and investigated with respect to their tribological effectiveness in SBMF. In a first step, requirements regarding necessary adaptions of the friction values for two SBMF processes are numerically defined. Based on the requirements different tailored surfaces are presented and analyzed regarding their tribological influence. Finally, the potential of surface modifications to improve SBMF processes is shown.
TL;DR: In this paper, a numerical simulation of the joining process was developed to visualize the material flow patterns and temperature distribution and to correlate the microstructure to the hardness behavior, and the weld nugget is composed of alternating layers of 7075 and 2017A.
Abstract: Dissimilar aluminum alloy sheets of 2017A-T451 and 7075-T651 (6 mm thickness) were friction stir welded in a butt weld configuration. A numerical simulation of the joining process was developed to visualize the material flow patterns and temperature distribution and to correlate the microstructure to the hardness behavior. Due to the complementary downward flow of surface material into the workpiece thickness and upward flow of mid-plane and bottom-plane material, the weld nugget is composed of alternating layers of 7075 and 2017A. These layers have unique temperature histories depending on the material’s initial location within the cross section; therefore, they also have distinctive precipitate distributions. Supersaturated surface material flows into the process zone and forms a core in which GP zones reprecipitate upon cooling. Mid-plane and bottom-plane material flow toward the workpiece surface and encompass the surface material core. Within this region, the weld temperatures overage the equilibrium θ phase in 2017A, decreasing the hardness, and at the same time, dissolve the equilibrium η/T phase in the 7075, leading to reprecipitation of GP zones upon cooling and a hardness recovery.
TL;DR: In this paper, the effect of tilt angle and process parameters such as rotational speed and traverse speed on material flow path was studied and the results indicated that the tilt angle is an effective factor on forging of material behind of pin in the advancing side and also in the upper portion of channel roof imperfections.
Abstract: Material flows during friction stir processes are very complex and not fully understood. Although the most literature reviews are presenting for material flow path, but Modified Friction Stir Channeling (MFSC) is a novel process based on Friction Stir Processing (FSP), which is being utilized to produce internal channel in Monolithic plates. A new flow pattern, in this study, is proposed to investigate material flow path and channel formation mechanism. The validity of this model is demonstrated by observing the cross-section and created keyhole using stop-action technique. The main difference between Friction Stir Channeling (FSC) and MFSC is the tilt angle. The effect of tilt angle and process parameters such as rotational speed and traverse speed on material flow path is studied. The results indicate that the tilt angle is an effective factor on forging of material behind of pin in the Advancing Side (AS) and also in the upper portion of channel roof imperfections. The rotational speed is an effective parameter on extruded material around the tool pin body and the extracted material in front of tool pin, because of the changing in the slip–stick condition and generated heat by tool. Traverse speed was an effective parameter on forging action of material and to keep material nearby tool pin in the behind of pin.
TL;DR: In this article, the authors investigated the material flow system of paper in Taiwan, and developed a supply chain network of paper flows, and estimated the reduction potential with a material input-output Markov chain model which maps the distribution and loss of materials on the supply chain processes.
TL;DR: In this article, the deformation behavior and the interactive effects of material microstructure and deformation temperature on forming quality of the fabricated micropart were investigated and the mesoformed part was extensively examined.
TL;DR: In this paper, the effects of tool rotation and feed rate on the material flow were analyzed by analyzing the maximum shear strength, Vickers microhardness, and optical observations.
Abstract: Dissimilar lap joints were produced by friction stir welding (FSW) out of Ti6Al4V titanium alloy and AA2024 aluminum alloy sheets. The joints, welded with varying tool rotation and feed rate, were studied by analyzing the maximum shear strength, Vickers microhardness and optical observations. A dedicated numerical model, able to take into account the presence of the two different alloys, was used to highlight the effects of the process parameters on temperature distribution, strain distribution, and material flow. The combined analysis of experimental measurements and numerical predictions allowed explaining the effects of tool rotation and feed rate on the material flow. It was found that tool rotation had a larger impact on the joint effectiveness with respect to feed rate. A competition between material mixing and heat input occurs with increasing tool rotation, resulting in higher joint strength when lower values of tool rotation are used.
TL;DR: In this paper, the authors investigated material flow behavior in similar aluminium alloy and magnesium alloy sheet lap welds produced by friction stir spot welding and found that dominant flow patterns near the shoulder edge were observed for similar Al welds, whereas high intensity outward spinning flows at the pin periphery for the similar Mg weld.
Abstract: This study investigated material flow behaviour in similar aluminium alloy and magnesium alloy sheet lap welds produced by friction stir spot welding. The material flows around the tool pin and shoulder were visualised through the tracer material technique, and schematic illustrations were made to clarify the induced material flow direction and intensity. The material flow observations described that the pin part provided the outward spinning motion of the material, while the shoulder part generated a centrifugal effect at the edge for downward flow/hooking. Induced material flow intensity suggested that dominant flow patterns near the shoulder edge were observed for the similar Al welds, whereas high intensity outward spinning flows at the pin periphery for the similar Mg welds. As a result, the material flow under the pin and shoulder of the tool explained that the morphology of the failure mode was highly dependent on the tool geometry and the alloy material adopted.
TL;DR: In this article, tracer materials as inserts have been used to study the material flow during friction stir spot welding (FSSW) of DP590 steel of 16mm thickness and a PCBN tool with convex scrolled shoulder was used for welding.
TL;DR: The Resource Efficient Scheduling (RES) tool as discussed by the authors is an extension of this work, applying the material flow assessment framework to a complex multi-product and multi-site manufacturing system scenario.
TL;DR: In this paper, the axial dispersion coefficient of rotating drums has been extended to include the effect of bulk flow properties by studying a number of cohesive powders, and it has been shown that the material flow properties correlated significantly with axial particle dynamics.
TL;DR: In this paper, a time dependent Eulerian thermal/material flow model of friction stir welding was developed and applied to the dissimilar joining of pure copper and aluminum 1050-H16 alloy to investigate the maximum penetration of base metals.
Abstract: A time dependent Eulerian thermal/material flow model of friction stir welding was developed and applied to the dissimilar joining of pure copper and aluminum 1050-H16 alloy to investigate the maximum penetration of base metals. Thermal and material flow analysis was done with the assumed velocity field in the stir zone and considering a thermal source of energy obtained from the both Coulomb type of friction and the loss of shear stress in a non-Newtonian viscous behavior of metal flow. The developed model was used to estimate temperature gradient and penetration of material under three different conditions of tool offset and compared with the experimental results. The model shows that the penetration of the base metals is closely related to tool offset. In all of the cases, the metal fixed in the advancing side is copper. Nevertheless, when considering tool offset in the copper side and also when considering tool offset in the aluminum side, penetrating metals are copper and aluminum, respectively. Also, the model shows that the maximum temperature achieved in the base metals significantly depends on the tool offset.
TL;DR: In this article, the material point method is proposed as a framework to model friction stir forming, which allows for the development of a fully coupled thermo-mechanical model which includes heat transfer processes due to plastic dissipation as well as frictional heating.
TL;DR: In this paper, the effects of welding parameters (including oscillation frequency, oscillation amplitude, friction pressure, and forging pressure) on material flow behavior were investigated, and it was shown that material flow velocity increases with increasing friction time and decreases with increasing forging time.
Abstract: Linear friction welding (LFW) of Ti6Al4V titanium alloy was simulated using 3D coupled thermo-mechanical finite element method. Effects of welding parameters (including oscillation frequency, oscillation amplitude, friction pressure, and forging pressure) on material flow behavior were investigated. Results of numerical simulation show that material flow velocity increases with increasing friction time and decreases with increasing forging time. Material flow velocity increases, and more material flows toward the edges of friction surface with increasing oscillation frequency, oscillation amplitude, and friction pressure at the friction stage. A reasonable axial shortening is beneficial to extrude the oxide out of deformable component. When the dimension of friction surface is 11.8 mm perpendicular to the oscillation direction and the oscillation amplitude is less than 2.5 mm, the axial shortenings at the friction stage and at the forging stage are respectively bigger than 4 and 0.65 mm in order to achieve the self-cleaning mechanism of LFW.
TL;DR: In this paper, a 2-Hi micro rolling mill has been successfully built for ultra-thin SUS 304 stainless steel strip and the experimental results show that the micro rolling deformation of ultra thin strip is influenced by size effect which results from the specimen size difference and this size effect is embodied in the flow stress and the friction coefficient.
Abstract: The demand for miniaturized parts and miniaturized semi-finished products is increasing nowadays, because microforming processes can improve production rate and minimize material waste due to less forming passes. However, traditional macro metal forming processes and modelling cannot be simply scaled down to produce miniaturized micro parts. In this study, a 2-Hi micro rolling mill has been successfully built. Experimental and numerical investigations on the micro rolling process for ultra-thin SUS 304 stainless steel strip have been conducted. The experimental results show that the micro rolling deformation of ultra-thin strip is influenced by size effect which results from the specimen size difference and this size effect is embodied in the flow stress and the friction coefficient. Analytical and finite element (FE) models in describing size effect related phenomena, such as flow stress, friction, rolling force and deformation behaviour, are proposed. The material surface constraint and the material deformation mode are critical in determination of material flow stress curve. The analysis of surface roughness evolution with rolling conditions has also been performed. The identified analysis on deformation mechanics provides a basis for further exploration of the material behaviour in plastic deformation of micro scale and the development of micro scale products via micro rolling.
TL;DR: In this paper, the authors analyzed the differences between incipient and repeatable material flow in the incremental sheet-bulk metal forming (SBMF) of gears produced by indentation along the direction perpendicular to the sheet thickness.
Abstract: This paper analyses the differences between incipient and repeatable material flow in the incremental sheet-bulk metal forming (SBMF) of gears produced by indentation along the direction perpendicular to the sheet thickness. The underfilling of the punch cavity during the first indentation, which prevents the production of sound disk gears, is explained on the basis of constrained material flow under material strain hardening. A solution based on the utilization of a tailored disk blank is proposed to overcome this defect. The geometry of the tailored disk blank is determined by means of finite element analysis, and the overall methodology involved material characterization and experimentation with DC04 mild steel. The discussion on the extent of the plastic deformation region under constrained and free-material flow during indentation is complemented by experimental results obtained with a flat punch in rectangular sheet blanks of aluminium EN AW-1050A.
TL;DR: In this paper, a streamline approach based on a cubic Bezier formulation is used to investigate the material flow during vortex extrusion (VE) and the velocity field and upper bound terms are calculated based on the proposed mathematical model in order to estimate the process load.
TL;DR: In this paper, a material flow of used mobile phones with quantitative information was illustrated and a sensitivity analysis was applied to clarify important factors in reducing material consumption and environmental impact, and the authors concluded that sensitivity analysis of material flow is a useful method in determining proper strategy of treatment of used products.
TL;DR: In this article, the material flow and thermal behavior of a 7 × × × aluminum alloy profile during an entire extrusion cycle are investigated numerically and experimentally, and a thermo-mechanical finite element model based on DEFROM-3D is built, and the transient extrusion process of the profile is simulated.
Abstract: Aluminum profile extrusion involves complex thermal, tribological, and mechanical interactions; thus, material flow and thermal behavior during extrusion process are very complicated. In this work, the material flow and thermal behavior of a 7 × × × aluminum alloy profile during an entire extrusion cycle are investigated numerically and experimentally. Hot compression tests are firstly carried out, and inverse analysis method is used to identify the material parameters of AA7N01 in Arrhenius constitutive model. The calculated global error is only 6.2 % between the predicted and experimental force–displacement curves, which verifies that the proposed model and obtained material parameters can describe well the rheological behavior of this alloy at elevated temperatures. Then a thermo-mechanical finite element model based on DEFROM-3D is built, and the transient extrusion process of the profile is simulated. By numerically analyzing the nose-end shape of the extruded profile, the evolution curves of exit temperature and of extrusion load, material flow and thermal behavior during extrusion process are investigated, respectively. Practical extrusion experiments verify the numerical model and results. Additional microstructure examination with electron backscatter diffraction (EBSD) technique also shows fine grains with the uniform grain size of about 9 μm on different locations of the extruded profile. Therefore, the material constitutive model and numerical model of extrusion process built in this work are capable enough to provide theoretical guidance in optimizing process parameters and designing extrusion dies.