scholarly journals Designing a kinematic module with rounding to model the processes of combined radial-longitudinal extrusion involving a tool whose configuration is complex

2021 ◽  
Vol 2 (1 (110)) ◽  
pp. 81-89
Author(s):  
Natalia Hrudkina ◽  
Igramotdin Aliiev ◽  
Oleg Markov ◽  
Iurii Savchenko ◽  
Liudmyla Sukhovirska ◽  
...  
Keyword(s):  
Velocity Field ◽  
Energy Method ◽  
Cutting Forces ◽  
Complex Form ◽  
Cold Extrusion ◽  
Preliminary Assessment ◽  
Industrial Implementation ◽  
Optimal Value ◽  
Estimation Scheme ◽  
Force Mode

It is advisable that parts whose shape is complex and which are made from solid or hollow blanks should be made by means of transverse and combined radial-longitudinal extrusion. The variation of manufacturing modes, tool configurations (in the form of chambers and rounding of the transitional sections of matrices) requires an adequate preliminary assessment of the force regime and the features of part shape formation. This paper has proposed a curvilinear kinematic module of the trapezoidal form for modeling radial-longitudinal extrusion processes in the presence of matrix rounding. Given the impossibility of using a quarter-circle boundary for the kinematically assigned possible velocity field, it has been proposed to use approximate curves in the form of z1(r) and z2(r). Taking into account the slightest deviation in the length of the arc of the approximate curve z1(r) and the area of the curvilinear trapezoid bounded by it relative to a quarter of the circle (not exceeding 0.8 % for any ratio), it has been recommended using this particular replacement. We have performed calculations of the value of the reduced deformation pressure inside the kinematic module with rounding taking into consideration the power of cutting forces at the border with adjacent kinematic modules. As an example, the devised module with rounding embedded in the estimation scheme of radial extrusion was analyzed. A significant impact of friction conditions on the force mode and the corresponding optimal value of the rounding radius have been identified. The resulting kinematic module makes it possible to expand the capabilities of the energy method for modeling cold extrusion processes involving the tools of complex form according to new deformation schemes. That could contribute to preparing recommendations on the optimal tool configuration and more active industrial implementation of these processes

scholarly journals Blow-up criterion for the density dependent inviscid Boussinesq equations

2020 ◽  
Vol 2020 (1) ◽  
Author(s):  
Li Li ◽  
Yanping Zhou
Keyword(s):  
Velocity Field ◽  
Energy Method ◽  
Blow Up ◽  
A Priori Estimates ◽  
A Priori ◽  
Boussinesq Equations ◽  
Smooth Solutions ◽  
Density Dependent ◽  
Priori Estimates ◽  
Blow Up Criterion

Abstract In this work, we consider the density-dependent incompressible inviscid Boussinesq equations in $\mathbb{R}^{N}\ (N\geq 2)$ R N ( N ≥ 2 ) . By using the basic energy method, we first give the a priori estimates of smooth solutions and then get a blow-up criterion. This shows that the maximum norm of the gradient velocity field controls the breakdown of smooth solutions of the density-dependent inviscid Boussinesq equations. Our result extends the known blow-up criteria.

Estimation of Dynamic Forces in Very High-Speed Impact Forging

1966 ◽  
Vol 88 (4) ◽  
pp. 369-372 ◽  
Author(s):  
M. J. Hillier
Keyword(s):  
Approximate Solution ◽  
Velocity Field ◽  
Plane Strain ◽  
Energy Method ◽  
Coulomb Friction ◽  
High Speed ◽  
Admissible Velocity ◽  
High Speed Impact ◽  
Dynamic Forces ◽  
Very High

A study is made of three methods of estimating die loads in impact forging: By approximate solution of the equations of equilibrium; by an energy method, assuming plane sections remain plane; and using the energy method in association with a kinematically admissible velocity field. Results are given for die pressures and die loads for axisymmetric and plane-strain forging of disks and slabs with smooth dies, perfectly rough dies, and for the case of Coulomb friction.

The Design and Simulation of Vibrate Impact Extrusion Die

2012 ◽  
Vol 201-202 ◽  
pp. 829-833
Author(s):  
Tong Xing ◽  
Xiao Long Feng ◽  
Liang Fu
Keyword(s):  
Flow Stress ◽  
Velocity Field ◽  
Material Flow ◽  
Room Temperature ◽  
Simulation Analysis ◽  
Conventional Technique ◽  
Flow Speed ◽  
Cold Extrusion ◽  
Extrusion Force ◽  
Extrusion Die

As conventional technique of cold extruding process face the problems that the equipment must provide large extrusion force during the workpiece extruding process, it has huge flow stress of the material and the frictional force between the mould and blank against the material flow under room temperature. To solve these problems, this article put forward a cold extruding mould with vibration. By simulation analysis of conventional and vibration of cold extrusion of travel load and velocity field, the force of vibration extrusion is reduced by 54% than that of conventional cold extrusion; therefore the forming surface of the parts and the material flow speed of vibration cold extrusion is greatly improved

Modeling and Analysis of Spindle with Active Magnetic Bearings for High-Speed Milling Process

2015 ◽  
Vol 32 (2) ◽  
pp. 131-141
Author(s):  
M. Barkallah ◽  
A. Bouaziz ◽  
S. Bouaziz ◽  
J.-Y. Choley ◽  
M. Haddar
Keyword(s):  
Cutting Forces ◽  
High Speed ◽  
System Modeling ◽  
Complex Form ◽  
Milling Process ◽  
Work Piece ◽  
Force Model ◽  
High Speed Milling ◽  
Modeling And Analysis ◽  
The Impact

AbstractThe high speed milling represents the most important process to produce parts in different fields such as aeronautics, automotive and mould. It allows obtaining parts with complex form and with the best surface quality. So, it remains essential to understand the impact of both the cutting force model and its parameters on the tool tip response. Consequently, the mastering of chatter vibration in milling and surface properties of the work piece is essential. In this paper, the simulation of machining is applied to determine the cutting forces distribution. A spindle system modeling is presented using a new approach: Both rigid and flexible modes of the spindle's shaft are taken into account. The shaft is discretized with the Timoshenko beam finite elements with different circular sections. Nonlinear electromagnetic loads exerted by AMBs are computed in terms of the nominal air gap between bearings and spindle, the control current and the displacement of each node. A parametric study is performed to determine the influence of some parameters, such as the feed rate, the tangential cutting coefficient, the spindle speed and the axial depth of the cut on the cutting forces and the chatter vibrations in milling.

Procedure for Maximizing Phonological Information from Single-Word Responses

1984 ◽  
Vol 15 (4) ◽  
pp. 267-274 ◽  
Author(s):  
Harriet B. Klein
Keyword(s):  
Phonological Information ◽  
Single Word ◽  
Preliminary Assessment ◽  
Target Attainment ◽  
Phonological Processes ◽  
Step Procedure ◽  
Yield Information ◽  
Assessment Measure ◽  
Busy Clinician ◽  
Planning Intervention

Formal articulation test responses are often used by the busy clinician as a basis for planning intervention goals. This article describes a 6-step procedure for using efficiently the single-word responses elicited with an articulation test. This procedure involves the assessment of all consonants within a word rather than only test-target consonants. Responses are organized within a Model and Replica chart to yield information about an individual's (a) articulation ability, (b) frequency of target attainment, substitutions, and deletions, (c) variability in production, and (d) phonological processes. This procedure is recommended as a preliminary assessment measure. It is advised that more detailed analysis of continuous speech be undertaken in conjunction with early treatment sessions.

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