Simulation, performance, and experimental validation of a high-speed traversing/positioning mechanism using electrorheological clutches

1998 ◽  
Author(s):  
Andrew R. Johnson ◽  
William A. Bullough ◽  
Richard C. Tozer ◽  
John Makin
Keyword(s):  
High Speed ◽  
Experimental Validation ◽  
Simulation Performance

On the dynamic stability of high-speed gas bearings: stability study and experimental validation

2011 ◽  
Vol 2 (2) ◽  
pp. 342-351
Author(s):  
T. Waumans ◽  
J. Peirs ◽  
J. Reynaerts ◽  
F. Al-Bender
Keyword(s):  
Dynamic Stability ◽  
Stability Problem ◽  
High Speed ◽  
Experimental Validation ◽  
Stability Study ◽  
Gas Bearings ◽  
Aerostatic Bearings ◽  
Bearing Dynamics ◽  
Wide Operating ◽  
Operating Temperature Range

For high-speed applications, gas lubricated bearings offer very specific advantages over other,more conventional bearing technologies: a clean and oil-free solution, virtually wear-free operation, lowfrictional losses, wide operating temperature range, etc. However, the principal drawback involved in theapplication of high-speed gas bearings concerns the dynamic stability problem. Successful applicationtherefore requires control of the rotor-bearing dynamics so as to avoid instabilities.After a detailed study of the dynamic stability problem and the formulation of a convenient stability criterium,a brief overview is given of the currently existing bearing types and configurations for improving the stability.In addition, three strategies are introduced: (i) optimal design of plain aerostatic bearings; (ii) modification ofthe bearing geometry to counteract the destabilising effects in the gas film; and (iii) introduction of dampingexternal to the gas film as to compensate for the destabilising effects.These strategies are worked out into detail leading to the formulation of a series of design rules. Theireffectiveness is validated experimentally at a miniature scale. In recent experiments a rotational speed of1.2 million rpm has been achieved with a 6 mm rotor on aerodynamic journal bearings, leading to a recordDN-number of 7.2 million.

Stochastic Modeling of a High Speed Composite Flywheel for Energy Storage

2018 ◽  
Author(s):  
Matthew E. Riley ◽  
Justin Pettingill
Keyword(s):  
Magnetic Field ◽  
Stochastic Models ◽  
High Speed ◽  
Experimental Validation ◽  
Electromagnetic Response ◽  
Finite Element Models ◽  
Composite Flywheel ◽  
Optimal Geometry ◽  
Micromechanics Models ◽  
Supporting Materials

This work will demonstrate the development and experimental validation of the stochastic models to predict the composite material’s mechanical and electromagnetic response as a function of the constituent reinforcing materials. First, stochastic micromechanics models will be developed for the case of multiple disparate supporting materials. These micromechanics models will then be validated against traditional finite element models and experimental results over the feasible parameter space. The developed models will then be utilized to define the optimal geometry of the composite flywheel including constraints such as displacement, stress, flux, magnetic field density, and manufacturability.

Experimental Validation of a Tuning Algorithm for High-Speed Filters

2007 ◽  
Author(s):  
G. Matarrese ◽  
C. Marzocca ◽  
F. Corsi ◽  
S. D'Amico ◽  
A. Baschirotto
Keyword(s):  
High Speed ◽  
Experimental Validation

Analytical Prediction of the Chip Back-Flow Angle in Machining With Restricted Contact Grooved Tools

2003 ◽  
Vol 125 (2) ◽  
pp. 210-219 ◽  
Author(s):  
N. Fang ◽  
I. S. Jawahir
Keyword(s):  
High Speed ◽  
Experimental Validation ◽  
Chip Thickness ◽  
Interfacial Stress ◽  
Tool Geometry ◽  
Analytical Prediction ◽  
Flow Angle ◽  
Back Flow ◽  
Definition Of ◽  
The Given

This paper develops a new analytical model to predict the chip back-flow angle in machining with restricted contact grooved tools. The model is derived from a recently established universal slip-line model for machining with restricted contact cutaway tools. A comprehensive definition of the chip back-flow angle is presented first, and based on this, a quantitative analysis of the chip back-flow effect is established for a given set of cutting conditions, tool geometry, and variable tool-chip interfacial stress state. The model also predicts the cutting forces, the chip thickness, and the chip up-curl radius. A full experimental validation of the analytical predictive model involving the use of high speed filming technique is then presented for the chip back-flow angle. This validation provides a range of feasible/prevalent tool-chip interfacial frictional conditions for the given set of input conditions.

Design of a Crank-Slider Spool Valve for Switch-Mode Circuits With Experimental Validation

2017 ◽  
Vol 140 (6) ◽  
Author(s):  
Shaun E. Koktavy ◽  
Alexander C. Yudell ◽  
James D. Van de Ven
Keyword(s):  
Flow Rate ◽  
High Speed ◽  
Experimental Validation ◽  
Viscous Friction ◽  
Transition Time ◽  
Switching Frequency ◽  
Experimental Demonstration ◽  
High Switching Frequency ◽  
Switch Mode ◽  
Spool Valve

A challenge in realizing switch-mode hydraulic circuits is the need for a high-speed valve with fast transition time and high switching frequency. The work presented includes the design and modeling of a suitable valve and experimental demonstration of the prototype in a hydraulic boost converter. The design consists of two spools driven by crank-sliders, designed for 120 Hz maximum switching frequency at a flow rate of 22.7 lpm. The fully open throttling loss is designed for <2% of the rated pressure of 34.5 MPa. The transition time is less than 5% (0.42 ms at 120 Hz) of the total cycle and the duty cycle is adjustable from 0 to 1. Leakage and viscous friction losses in the design are less than 2% of the rated hydraulic energy per cycle. The experimental results agreed well with the model resulting in a 3% variation in transition time. The use of the high-speed valve in a pressure boosts converter demonstrated boost ratio capabilities of 1.08–2.06.

Three-Component Receptance Coupling Substructure Analysis for Tool Point Dynamics Prediction

2005 ◽  
Vol 127 (4) ◽  
pp. 781-790 ◽  
Author(s):  
Tony L. Schmitz ◽  
G. Scott Duncan
Keyword(s):  
Finite Difference ◽  
High Speed ◽  
Experimental Validation ◽  
Second Generation ◽  
Standard Test ◽  
High Speed Machining ◽  
Receptance Coupling ◽  
Substructure Analysis ◽  
Receptance Coupling Substructure Analysis ◽  
Tool Assembly

In this paper we present the second generation receptance coupling substructure analysis (RCSA) method, which is used to predict the tool point response for high-speed machining applications. This method divides the spindle-holder-tool assembly into three substructures: the spindle-holder base; the extended holder; and the tool. The tool and extended holder receptances are modeled, while the spindle-holder base subassembly receptances are measured using a “standard” test holder and finite difference calculations. To predict the tool point dynamics, RCSA is used to couple the three substructures. Experimental validation is provided.

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