Frequency Response Evaluation of Multiple Accelerometers Using a Modal Data Acquisition System
Final rept. 1 Oct 1986-1 Aug 1987
AIR FORCE RESEARCH LAB WRIGHT-PATTERSON AFB OH AIR VEHICLES DIRECTORATE
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This report describes a technique to get complete frequency response calibrations of 15 accelerometer channels at a time. The accelerometers were mounted to a rigid circular plate attached to a shaker excited by random noise. A digital pulse code modulation data acquisition system acquired and stored the 15 responses. Using the time multiplexed, digital responses, each transducer frequency response was computed by deriving transfer functions between the 15 unknown transducers and a DC responding reference accelerometer. Before using this multiple accelerometer calibration technique, several single channel laboratory calibrations were performed using four methods. The multiple accelerometer technique was tested in the laboratory and on a F-16 wing ground vibration test. A total of 37 accelerometers were evaluated over a range of 0 to 100 Hz. Exciting multiple accelerometers ensures calibration of each transducer at the same temperature, humidity, and force input levels. The technique provides a quick, automated, end-to-end frequency response calibration. Sensitivities versus frequency are close to those obtained using single accelerometer calibration techniques.
- Test Facilities, Equipment and Methods