Mechanical and Electrical Run-Out Removal on a Precision Rotor-Vibration Research Spindle

1997 ◽  
Vol 119 (2) ◽  
pp. 216-220 ◽  
Author(s):  
G. A. Horattas ◽  
M. L. Adams ◽  
F. Dimofte
Keyword(s):  
Steady State ◽  
Experimental Determination ◽  
Journal Bearing ◽  
Dynamic Performance ◽  
Data Acquisition System ◽  
Small Range ◽  
Rotor Vibration ◽  
System 1 ◽  
Better Than

Experimental determination of both steady-state and dynamic performance of a journal bearing requires the use of a high precision spindle with a vanishingly small range of run-out. This was achieved by first eliminating the mechanical run-out of the spindle by grinding the journal specimen while rotating in place. Once the mechanical run-out was removed, the electrical run-out sensed by the displacement proximity-probe-transducers was also removed. Using this procedure the mechanical and electrical run-outs of a research spindle were reduced to less than 0.2 micron (10 μin.), which is better than the resolution of the data acquisition system, 1 micron (50 μin.).

scholarly journals Simple Method for Estimating the Contribution of Neighbouring n-beam Interactions to Two-beam Structure Factors

1988 ◽  
Vol 41 (3) ◽  
pp. 469
Author(s):  
HJ Juretschke ◽  
HK Wagenfeld
Keyword(s):  
Experimental Determination ◽  
Structure Factor ◽  
Beam Structure ◽  
Simple Method ◽  
Experimental Configuration ◽  
Structure Factors ◽  
Special Cases ◽  
Better Than

Unless special precautions are taken, the experimental determination of two-beam structure factors to better than 1 % may include contributions from neighbouring n-beam interactions. In any particular experimental configuration, corrections for such contributions are easily carried out using the modified two-beam structure factor formalism developed recently (Juretschke 1984), once the full indexing of the pertinent n-beam interactions is known. The method is illustrated for both weak and strong primary reflections and its applicability in special cases, as well as for less than perfect crystals, is discussed.

An Experimental Determination of the Relationship between Lift and Aerodynamic Power in Calliphora Erythrocephala and Phormia Regina

1972 ◽  
Vol 56 (1) ◽  
pp. 31-36
Author(s):  
JAMES WOOD
Keyword(s):  
Steady State ◽  
Experimental Determination ◽  
Insect Flight ◽  
Phormia Regina ◽  
Calliphora Erythrocephala ◽  
The Relationship

Lift and aerodynamic power were calculated for Calliphora and Phormia using assumptions which maximized and minimized the ratio of aerodynamic power to lift. The ratios of aerodynamic power to lift calculated by these methods, which do not rely on the assumption that steady-state aerodynamics applies to insect flight, are in agreement with results calculated by others using steady-state aerodynamics.

Experimental Determination of Oscillatory Lift and Moment Distributions on Fully Submerged Flexible Hydrofoils

1963 ◽  
Vol 7 (04) ◽  
pp. 24-41
Author(s):  
Guido E. Ransleben ◽  
H. Norman Abramson
Keyword(s):  
Steady State ◽  
Wind Tunnel ◽  
Aspect Ratio ◽  
Experimental Determination ◽  
Theoretical Predictions ◽  
Wind Tunnel Data

Measured span wise distributions of steady state and oscillatory lift and moment on fully submerged cantilever hydrofoils are presented. The hydrofoils were of aspect ratio 5 rectangular platform, and were towed at speeds sufficiently low to avoid cavitation. The data are compared with theoretical predictions and wind-tunnel data previously obtained at higher values of reduced velocity.

Experimental Determination of the Dynamic Characteristics of a Two-Axial Groove Journal Bearing

1994 ◽  
Vol 37 (3) ◽  
pp. 534-542 ◽  
Author(s):  
Gregory J. Kostrzewsky ◽  
David V. Taylor ◽  
Ronald D. Flack
Keyword(s):  
Experimental Determination ◽  
Dynamic Characteristics ◽  
Journal Bearing

The experimental determination of trajectories in geometrically similar plastic flows

1978 ◽  
Vol 13 (1) ◽  
pp. 29-34 ◽  
Author(s):  
R N Roth
Keyword(s):  
Steady State ◽  
Experimental Determination ◽  
Experimental Method ◽  
Quasi Steady State ◽  
Experimental Accuracy ◽  
Geometric Similarity ◽  
Orthogonal Grid ◽  
Wedge Indentation ◽  
Strain Wedge

A new experimental method is presented for determining trajectories of flow for non-steady-state processes which exhibit geometric similarity (quasi-steady-state processes (1)∗). One process that is normally regarded as quasi-steady-state (plane strain wedge indentation) is investigated using this method. It is shown that this process satisfies the requirements of geometric similarity within experimental accuracy. Results are presented for wedge angles of 30°, 60° and 90° and a range of indentation depths up to approximately 3 mm. Finally, it is suggested how this method can be combined with well-known orthogonal-grid techniques to provide information for the calculation of effective strains throughout the deforming region.

A Waved Journal Bearing Concept-Evaluating Steady-State and Dynamic Performance With a Potential Active Control Alternative

1993 ◽  
Author(s):  
Florin Dimofte
Keyword(s):  
Steady State ◽  
Wave Amplitude ◽  
Journal Bearing ◽  
Load Capacity ◽  
Dynamic Stiffness ◽  
Dynamic Performance ◽  
Film Stability ◽  
Dynamic Coefficients ◽  
The Waves ◽  
Compressible Lubricant

Abstract Analysis of the waved journal bearing concept featuring a waved inner bearing diameter for use with a compressible lubricant (gas) is presented. The performance of generic waved bearings having either three or four waves is predicted for air lubricated bearings. Steady-state performance is discussed in terms of bearing load capacity, while the dynamic performance is discussed in terms of fluid film stability and dynamic coefficients. It was found that the bearing wave amplitude has an important influence on both steady-state and dynamic performance of the waved journal bearing. For a fixed eccentricity ratio, the bearing steady-state load capacity and direct dynamic stiffness coefficient increase as the wave amplitude increases. Also, the waved bearing becomes more stable as the wave amplitude increases. In addition, increasing the number of waves (e.g., four waves instead of three waves) reduces the waved bearing’s sensitivity to the direction of the applied load relative to the wave. However, the range in which the bearing performance can be varied decreases as the number of waves increases. Therefore, both the number and the amplitude of the waves must be properly selected to optimize the waved bearing design for a specific application. Another possibility is to use the waved bearing to actively control the rotor-bearing system dynamic coefficients via actively controlling the wave amplitude.

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