Nonlinear acoustic landmine detection experiment: Cylindrical drumlike landmine simulant buried in wetted or unwetted pea gravel
A laboratory experiment for studying acoustic landmine detection involves an 8 in. diameter, 4 in. tall drumlike landmine simulant buried two inches beneath the surface of a pea gravel medium in a cylindrical tank (9 in. O.D., 2 in. thick, 24 in. tall). The cylindrical column of gravel is supported...
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| Published in: | The Journal of the Acoustical Society of America Vol. 146; no. 4; p. 2783 |
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| Main Authors: | , |
| Format: | Journal Article |
| Language: | English |
| Published: |
01-10-2019
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| Online Access: | Get full text |
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| Summary: | A laboratory experiment for studying acoustic landmine detection involves an 8 in. diameter, 4 in. tall drumlike landmine simulant buried two inches beneath the surface of a pea gravel medium in a cylindrical tank (9 in. O.D., 2 in. thick, 24 in. tall). The cylindrical column of gravel is supported on the sides by the concrete wall, and underneath by the thin circular acrylic top plate of the simulant (which has a thick aluminum bottom plate). Above the surface, a fine spraying mister is controlled to wet the gravel at regular intervals. A porous system near the bottom of the tank drains off excess water. For airborne acoustic excitation two loud speakers are driven by an amplified swept tone (50–850 Hz). A laser Doppler vibrometer connected to a spectrum analyzer measures the particle velocity response across the surface. Nonlinear tuning curve responses were measured on the surface to compare the characteristic frequency shift of the resonant peak with amplitude for nonwetted or wetted gravel. Then, at fixed drive amplitude, the tuning curve response was measured at discrete scan locations across the gravel. Therefore, at any specific resonant frequency, the mode shape response of the coupled simulant-gravel system can be measured. |
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| ISSN: | 0001-4966 1520-8524 |
| DOI: | 10.1121/1.5136638 |