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.

A Methodology to Determine Work Material Flow Stress and Tool-Chip Interfacial Friction Properties by Using Analysis of Machining

Abstract: In this paper, we develop a methodology to determine flow stress at the machining regimes and friction characteristics at the tool-chip interface from the results of orthogonal cutting tests. We utilize metal cutting analysis originally developed by late Oxley and present some improvements. We also evaluate several temperature models in calculating the average temperatures at primary and secondary deformation zones and present comparisons with the experimental data obtained for AISI 1045 steel through assessment of machining models (AMM) activity. The proposed methodology utilizes measured forces and chip thickness obtained through a basic orthogonal cutting test. We conveniently determine work material flow stress at the primary deformation zone and the interfacial friction characteristics along the tool rake face. Calculated friction characteristics include parameters of the normal and frictional stress distributions on the rake face that are maximum normal stress Nmax, power exponent for the normal stress distribution, a, length of the plastic contact, lp, length of the tool-chip contact, lc, the average shear flow stress at tool-chip interface, kchip, and an average coefficient of friction, e, in the sliding region of the tool-chip interface. Determined flow stress data from orthogonal cutting tests is combined with the flow stress measured through split-hopkinson pressure bar (SHPB) tests and the Johnson-Cook work material model is obtained. Therefore, with this methodology, we extend the applicability of a Johnson-Cook work material model to machining regimes. DOI: 10.1115/1.2118767

Self-organizing manufacturing control: an industrial application of agent technology

Abstract: We present an auction-based approach to manufacturing control. Workpieces auction off their current task, while machines bid for tasks. When awarding a machine, a workpiece takes into account not only the machine's current work in process, but also the outgoing flow of materials. If a machine's outgoing stream is blocked, eventually the machine will not accept a new workpiece, thus blocking its input stream as well. As a result a capacity bottleneck is automatically propagated in the opposite direction of the material flow. A unique feature of this mechanism is that it does not pre-suppose any specific material flow; the current capacity bottleneck is always propagated in the opposite direction of the actual flow, no matter what this flow looks like. This paper includes a detailed analysis of the mechanism, including a formal proof of its freedom of deadlocks. DaimlerChrysler evaluated the new control approach as a bypass to an existing manufacturing line. A suite of performance tests demonstrated the industrial feasibility and the benefits of the approach.

Granular flow behaviour in the transverse plane of a partially filled rotating cylinder

Abstract: Material flow in partially filled rotating cylinders (rotary kilns) is encountered in many practical applications of material processing, for example incineration, calcination, grain drying, etc. The flow behaviour in the cross-section is important to other transport mechanisms such as mixing and energy distribution within the bed material. The paper describes an experimental study which was carried out with the objective of understanding and improving our predictive capabilities of the rheological behaviour of granular materials in rotary cylinders. Measurement techniques similar to that used in chute flows have been employed to measure flow characteristics, e.g. particle velocities, granular temperature, and solid concentration (in the shear layer developed between the free surface and the bulk of the bed) for different materials having a wide range of coefficients of restitution. The results of the experiments provide the necessary assumptions, constraints, and data for granular flows in partially filled rotating cylinders.