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.

Tribological measures for controlling material flow in sheet-bulk metal forming

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.

Furnace charging installation

Abstract: The delivery of charge material to the hearth of a pressurized blast furnace under the influence of gravity is accomplished without the necessity of changing the direction of material flow at a point exterior of the furnace The rate of flow of the charge material, which moves in a vertical stream, is controlled by a metering device including a pair of overlapping register elements which define a variable size aperture which remains generally symmetrical with respect to the stream axis

Equal channel angular extrusion of soft solids

Abstract: The influence of rheological properties of processed materials on deformation heterogeneity has been studied for the viscous flow of plasticine during equal channel angular extrusion (ECAE) through a rectangular die 2 θ = 90° without any external rounding φ = 0°. To perform the physical simulation of ECAE a hydraulic workbench and a plexiglass split die were fabricated. Application of an experimental circular grid technique for planar flow of plasticine billets allows us to investigate the formation of turbulence elements and a material dead zone. Theoretical material flow patterns, the characteristics of deformation non-uniformity, flow lines, the flow velocity fields, energy-power parameters and dead zone formation in the physical simulation of the ECAE in a rectangular die have been determined with a numerical finite-difference solution of the Navier–Stokes equation in the curl transfer form for the planar flow of viscous incompressible continua. Good agreement between theoretical and averaged experimental results was found. The legitimacy of an existing analogy between viscous liquid flow and polycrystalline plastic flow during ECAE has also been analyzed. This proposed technique may be useful when applied to the analysis of polymer flow with severe plastic deformation.

Statistical calibration and uncertainty quantification of complex machining computer models

Abstract: Finite element based machining process models are used in research and industry for process design and optimization These models require a constitutive description of the material behavior to accurately model and predict process responses such as cutting forces, temperatures, and residual stress Calibration of these models to low-strain uniaxial dynamic compression experiments can be troublesome since the machining process generally imposes much larger strains than uniaxial compression Calibration of finite element models directly to machining data is generally difficult since the models are computationally expensive and nonlinear optimization methods for estimating the unknown calibration parameters yield non-unique solutions and require many iterations In this work we utilize a nonstationary Gaussian Process surrogate model to emulate the finite element response and calibrate to experimental orthogonal cutting tests using a Bayesian inference framework We assume that the material yield behavior can be described by the Johnson-Cook material flow model We find that the nonstationary Gaussian Process model is an good surrogate for the complex finite element model Cutting forces measured from orthogonal tube turning experiments were used for calibration Validation is performed using a separate response variable - the cut chip thickness Calibration results illustrate a preference for material models with low hardening rates, which alleviates issues such as over-prediction of strain hardening behavior when using the Johnson-Cook material flow model The Bayesian formulation also captures the uncertainty in the Johnson-Cook parameters, which can be used to quantify the uncertainty in the machining process responses The methods presented here are general and can be used for more complex constitutive and tribological models for machining and other complex manufacturing processes