A successful military defense depends in part on the military’s ability to protect its personnel in combat. One way the military accomplishes this is through the use of protective structures. To validate the effectiveness of protective structures, a large military explosive ordnance test site in Virginia uses a lightweight, high-speed, portable PC-based data acquisition system. By measuring the magnitude of pressure waves created by the detonation of explosives across various locations around a structure, the engineers at this test site are able to determine each structure’s effectiveness, including its ability to deflect harmful pressure waves away from military personnel and equipment.

Application Summary
Increasing the survivability of military personnel and equipment exposed to destructive power has been a challenge for the military since the inception of warfare. When an explosive detonates, it creates a wavefront or pressure wave that is denser than steel. Traveling at supersonic speed, this highly dense wavefront can cause considerable damage. To shield military assets from this destructive power, military civil engineers construct protective enclosures of earth and building materials. These protective structures redirect the destructive pressure waves away from military personnel and equipment located inside.

To validate the effectiveness of earthen protective structures, the engineers of the Virginia explosive ordnance test site build full scale models, place pressure sensors at specific locations in and around the structures, and collect data during simulated front-line combat. The engineers connect these pressure sensors to a portable PC-based digitizer and configure it for a high-speed rising analog threshold trigger via Windows-based software. This allows the digitizer to wait for the explosion’s impulse before acquiring any data.

When the engineers detonate an explosive near the protective structure under test, the resulting explosion’s pressure wave excites the pressure sensors. The pressure sensors’ output is then amplified by a signal conditioner that passes it on to the portable digitizer as a linear analog signal. This analog signal triggers the portable digitizer, which then measures the magnitude of the pressure wave at each pressure sensor location for the duration of the blast. The portable digitizer’s speed enables it to capture the pressure-wave explosion data. With this data, the test site engineers are able to calculate important physical parameters such as the impulse imparted to objects within the explosion.

Ultimately, this data enables the test site engineers to improve the protective structure design so that it can effectively dampen and deflect destructive pressure waves. This information also enables them to test the effectiveness of explosive ordnance currently under development against fortifications commonly used by potential enemies and is useful for helping the military attain a maximum kill ratio for each shell design.

Potential Solution
Initially, the ordnance test site engineers evaluated several A/D plug-in boards and rejected them because they could not find software that easily and quickly enabled them to collect the required data.

IOtech’s Solution
The test site engineers selected the portable WaveBook for its included Out-of-the-Box software — WaveView. WaveView enables the engineers to choose from a variety of trigger types and makes it easy for them to quickly set up multiple experiments without having to write special programs for each.

Conclusion
The WaveBook’s high frequency acquisition, low-noise analog inputs, portability, Out-of-the-Box software, and overall versatility make it a perfect solution for this application as well as for other general-purpose data acquisition needs at the test site.

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