1 / 24

slide 1 - scott dewolf

niveditha
Download Presentation

slide 1 - scott dewolf

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

    2. Introduction Sensors & Sensor Design Experimental Mechanical sensitivity results Comparisons with other sensors Potentially significant mechanisms to sensor response

    3. The ATR Sensor Four 35mm piezo bimorphs mounted on the same plane Uses 4” PVC components Pressure sensitivity estimate:

    4. The ATR Sensor

    5. The FDS Sensor Also has four piezo bimorphs Used by F. Douglas Shields in wind noise correlation study1 Element is contained in PVC housing when deployed Pressure sensitivity estimate:

    6. The FDS Sensor

    7. The TEST Sensor Built to test seismic cancellation Uses two piezo bimorphs mounted to aluminum back-volume Pressure sensitivity estimate:

    8. The TEST Sensor

    9. Experimental Setup Tested motion both in-plane and out-of-plane Recorded on-axis and off-axis acceleration Measurements taken in sound isolation booth

    10. Experimental Setup

    11. Data Collection & Analysis Linear sweeps from 0.1Hz to 10Hz 1,000 second duration at 500Hz sampling Least-squares estimation to determine response magnitudes Scaled sensor response by calibrated on-axis accelerometer response Discarded data below 1Hz due to poor signal-to-noise conditions

    15. Results: Mechanical Sensitivity ATR and FDS sensors appeared less sensitive to in-plane motion (~10-1) TEST sensor responds almost identically to both types of motion above 4Hz ATR behaves nearly flat out-of-plane Both TEST & FDS sensors had appreciable response despite expected cancellation

    18. Minimum Detection Minimum detectable acceleration based on peak sensitivity & noise:

    19. Minimum Detection

    20. Barometric Effect? Starovoit and Martysevich showed pressure difference was not significant for MB20003 Analysis not done for Chaparral 5 Average peak displacement: Not significant relative to noise

    21. Seismic-to-Acoustic Coupling Starovoit and Martysevich also showed that induced pressure dominated mechanical response below ~1.5Hz for MB20003 Described as “piston effect” pressure sensitivity density of air speed of sound in air

    23. Conclusion Mechanical Sensitivity ATR: nearly flat mechanical response FDS & TEST sensors had nonlinear response that decreased with frequency Comparisons with other sensors Mechanical response comparable to Chaparral 5 Minimum detectable accelerations Possible response mechanisms Barometric effect not noticeable Coupled pressure wave dominates seismic response for all frequencies

    24. Acknowledgements Dr. Henry Bass, Dr. Carrick Talmadge & Mr. Claus Hetzer (NCPA) Mr. Shantharam Dravida (NCPA) UW-River Falls McNair Scholars Program Dr. Lowell McCann (UWRF) UAF Geophysical Institute

More Related