Unusual gyroscopic system eigenvalue behavior in high-speed planetary gears

2013 ◽  
Vol 332 (7) ◽  
pp. 1820-1828 ◽  
Author(s):  
Christopher G. Cooley ◽  
Robert G. Parker
Keyword(s):  
High Speed ◽  
Gyroscopic System ◽  
Planetary Gears

Critical Speeds, Divergence, and Flutter Instability in High-Speed Planetary Gears

2012 ◽  
Author(s):  
Christopher G. Cooley ◽  
Robert G. Parker
Keyword(s):  
High Speed ◽  
Critical Speed ◽  
Numerical Results ◽  
Planetary Gears ◽  
Critical Speeds ◽  
Flutter Instability ◽  
Divergence Instability ◽  
Translational Mode

The structured properties of the critical speeds and associated critical speed eigenvectors of high-speed planetary gears are given. Planetary gears have only planet, rotational, and translational mode critical speeds. Divergence instability is possible at speeds adjacent to critical speeds. Numerical results verify the critical speed locations. Divergence and flutter instabilities are investigated numerically for each mode type.

Vibration Properties of High-Speed Planetary Gears With Gyroscopic Effects

2012 ◽  
Vol 134 (6) ◽  
Author(s):  
Christopher G. Cooley ◽  
Robert G. Parker
Keyword(s):  
High Speed ◽  
Eigenvalue Problems ◽  
Planetary Gear ◽  
Vibration Modes ◽  
Planetary Gears ◽  
High Speeds ◽  
Wide Range ◽  
Modal Property ◽  
Gyroscopic Effects ◽  
Complex Valued

This study investigates the modal property structure of high-speed planetary gears with gyroscopic effects. The vibration modes of these systems are complex-valued and speed-dependent. Equally-spaced and diametrically-opposed planet spacing are considered. Three mode types exist, and these are classified as planet, rotational, and translational modes. The properties of each mode type and that these three types are the only possible types are mathematically proven. Reduced eigenvalue problems are determined for each mode type. The eigenvalues for an example high-speed planetary gear are determined over a wide range of carrier speeds. Divergence and flutter instabilities are observed at extremely high speeds.

A Lumped Parameter Model to Analyse the Dynamic Load Sharing in Planetary Gears with Planet Errors

2011 ◽  
Vol 86 ◽  
pp. 374-379 ◽  
Author(s):  
Xiao Yu Gu ◽  
Philippe Velex
Keyword(s):  
High Speed ◽  
Load Sharing ◽  
Lumped Parameter Model ◽  
Mesh Stiffness ◽  
Planetary Gears ◽  
Position Errors ◽  
Load Distributions ◽  
Lumped Parameter ◽  
Non Linear ◽  
Dynamic Load Sharing

A non-linear dynamic model of planetary gears is presented which accounts for planet position errors, time-varying non-linear mesh stiffness along with the interactions between deflections and instantaneous meshing conditions. The quasi-static load distributions agree well with the experimental results in the literature thus validating the contact simulation. Extensions towards high-speed behaviour are presented which show how dynamic effects may impact the instantaneous load sharing amongst the planets.

Dynamic imbalance of high-speed planetary gears

2017 ◽  
Vol 7 (1) ◽  
pp. 2-6 ◽  
Author(s):  
A Masoumi ◽  
M Barbieri ◽  
F Pellicano ◽  
A Zippo ◽  
M Strozzi
Keyword(s):  
High Speed ◽  
Planetary Gears

Interesting Eigenvalue Behavior in High-Speed Planetary Gears With Gyroscopic Effects

2013 ◽  
Author(s):  
Christopher G. Cooley ◽  
Robert G. Parker
Keyword(s):  
High Speed ◽  
Planetary Gear ◽  
Gyroscopic System ◽  
Critical Speeds ◽  
High Speeds ◽  
Lumped Parameter ◽  
Axially Moving ◽  
Gyroscopic Effects ◽  
Moving Media ◽  
Gyroscopic Systems

This study demonstrates interesting and unusual gyroscopic system eigenvalue behavior observed in a lumped-parameter planetary gear model. The focus of this work is on the eigenvalue phenomena that occur at especially high speeds rather than practical planetary gear behavior. The behaviors include calculation of exact trajectories across critical speeds, uncommon stability features near degenerate critical speeds, and unique stability transitions. These eigenvalue behaviors differ from those of other gyroscopic systems such as spinning disks, shafts, and rings, and axially-moving media.

Mechanical stability of high-speed planetary gears

2013 ◽  
Vol 69 ◽  
pp. 59-71 ◽  
Author(s):  
Christopher G. Cooley ◽  
Robert G. Parker
Keyword(s):  
High Speed ◽  
Mechanical Stability ◽  
Planetary Gears

Vibration Structure of Gyroscopic Planetary Gears

2011 ◽  
Author(s):  
Christopher G. Cooley ◽  
Robert G. Parker
Keyword(s):  
High Speed ◽  
Eigenvalue Problems ◽  
Planetary Gear ◽  
Vibration Modes ◽  
Planetary Gears ◽  
High Speeds ◽  
Wide Range ◽  
Mode Method ◽  
Complex Valued

This study investigates the vibration structure of high-speed, gyroscopic planetary gears. The vibration modes of these systems are complex-valued and speed dependent. Three mode types exist, and these are classified as planet, rotational, and translational modes. Each mode type is mathematically proven by the use of a candidate mode method. Reduced eigenvalue problems are determined for each mode type. The eigenvalues for an example high-speed planetary gear are determined over a wide range of carrier speeds. Divergence and flutter instabilities are observed at extremely high speeds.

Microfabrication research at the National Submicron Facility

1983 ◽  
Vol 41 ◽  
pp. 86-89
Author(s):  
E.D. Wolf
Keyword(s):  
Integrated Circuits ◽  
Particle Physics ◽  
High Speed ◽  
New Technology ◽  
High Energy ◽  
High Energy Particle ◽  
New Science ◽  
Wide Range ◽  
Intermediate Domain ◽  
Circuit Function

Most microelectronics devices and circuits operate faster, consume less power, execute more functions and cost less per circuit function when the feature-sizes internal to the devices and circuits are made smaller. This is part of the stimulus for the Very High-Speed Integrated Circuits (VHSIC) program. There is also a need for smaller, more sensitive sensors in a wide range of disciplines that includes electrochemistry, neurophysiology and ultra-high pressure solid state research. There is often fundamental new science (and sometimes new technology) to be revealed (and used) when a basic parameter such as size is extended to new dimensions, as is evident at the two extremes of smallness and largeness, high energy particle physics and cosmology, respectively. However, there is also a very important intermediate domain of size that spans from the diameter of a small cluster of atoms up to near one micrometer which may also have just as profound effects on society as “big” physics.

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