Topic
Material flow
About: Material flow is a research topic. Over the lifetime, 3050 publications have been published within this topic receiving 36844 citations. The topic is also known as: material stream.
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TL;DR: In this article, the three-dimensional flow of metal in friction stir welding (FSW) has been simulated based on computational fluid dynamics and conservation equations of mass, momentum, and energy were solved in three dimensions.
Abstract: In this research, the three-dimensional flow of metal in friction stir welding (FSW) has been simulated based on computational fluid dynamics. Conservation equations of mass, momentum, and energy were solved in three dimensions. The interactive force was imposed as boundary conditions on the tool/material boundary in the model. The strain rate- and temperature-dependent non-Newtonian viscosity was adopted for the calculation of metal flow. The distribution of temperature, velocity, and strain rate were simulated based on the above models. The simulated temperature distribution agreed well with the experimental results. The simulation results showed that the velocity on the pin was much higher than that on the shoulder. From the comparison between the simulation results and the experiments results, contours line, corresponding to strain rate = 4 s−1, reflected reasonably well the shape of stir zone, especially at the ground portion.
31 citations
TL;DR: A new friction model is developed, taking into account the sliding velocity between tools and workpiece, and it is confirmed that this model represents the state of the art in tribology.
Abstract: The finite element method is a powerful tool for the design and optimization of hot forming processes. In order to obtain high accuracy in simulation results, exact knowledge of the process conditions is required. Due to the fact that friction in the contact area has a significant impact on the material flow during the forming process, a realistic description of this boundary condition in the FE simulation is important for the usability of the simulation results. The most important influencing factors are the contact pressure, the roughness of the contact surfaces, the sliding velocity and the flow behavior of the material. Currently, only constant friction coefficients are considered in commercial finite element systems for the simulation of bulk metal forming processes. However, this description does not represent the state of the art in tribology. A new friction model is developed, taking into account the sliding velocity between tools and workpiece. This is confirmed by experimental and numerical investigations on model experiments and industrial process.
31 citations
TL;DR: In this paper, a model based on stochastic discrete-time controlled dynamical systems is developed to derive optimal policies for controlling the material flow in supply networks, where each node in the network is described as a transducer such that the dynamics of the material and information flows within the entire network can be expressed by a system of first-order difference equations, where some inputs to the system act as external disturbances.
Abstract: We develop a model based on stochastic discrete-time controlled dynamical systems in order to derive optimal policies for controlling the material flow in supply networks. Each node in the network is described as a transducer such that the dynamics of the material and information flows within the entire network can be expressed by a system of first-order difference equations, where some inputs to the system act as external disturbances. We apply methods from constrained robust optimal control to compute the explicit control law as a function of the current state. For the numerical examples considered, these control laws correspond to certain classes of optimal ordering policies from inventory management while avoiding, however, any a priori assumptions about the general form of the policy.
31 citations
TL;DR: In this article, the velocity field and mixing of granular material as it flows over a single blade are studied. And the results agree qualitatively with a simple model for granular mixing.
30 citations
TL;DR: The framework and methods developed in this study provide accounting templates that can be used for material flow analysis of cities at different stages of development both in China and elsewhere, thereby permitting a more unified and comparable accounting and analysis between studies.
30 citations