A mechanical system damping measurement technique using a one-degree-of-freedom (1DOF) cylindrical gas bearing
Abstract
An experimental investigation was conducted in the Airflow Calibration Laboratory (ACL) to separate the total rolling moment of rigid and nonrigid mechanical systems into viscous damping and coulomb rolling-moment components. The test technique consisted of measuring roll rate decay of these rigid and nonrigid mechanical systems on a one-degree-of-freedom (1 DOF) cylindrical gas bearing. To better understand the 1 DOF bearing tare damping, a significant amount of information was collected about the operational characteristics of the 1DOF cylindrical gas bearing at certain test conditions. The 1DOF bearing characteristics and test technique are described in this report. The application of the test technique developed for this investigation could be beneficial for determining damping properties of other mechanical systems such as turbomachinery, space structures, gas/ball bearings, and high-damping-capacity materials. The primary measurement uncertainties for the present investigation were determined as follows: +/- 0.01 deg/sec for roll rate obtained with a one-spot tachometer ring, +/- 0.001 in.-lbf for viscous damping moment, or, in terms of energy dissipation, +/- 1 mW. The coulomb rolling-moment uncertainty could not be established because of its variable nature.
- Publication:
-
Final Report
- Pub Date:
- August 1993
- Bibcode:
- 1993aedc.rept.....R
- Keywords:
-
- Cylindrical Bodies;
- Dynamic Structural Analysis;
- Gas Bearings;
- Large Space Structures;
- Mechanical Measurement;
- Rolling Moments;
- Spacecraft Structures;
- Structural Vibration;
- Turbomachinery;
- Vibration Damping;
- Viscous Damping;
- Aerospace Systems;
- Air Flow;
- Ball Bearings;
- Calibrating;
- Degrees Of Freedom;
- Energy Dissipation;
- Moments Of Inertia;
- Tachometers;
- Mechanical Engineering