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Sprinkling attempts on tanks and buildings


WTD 91 in Meppen is one of ten defense technology and defense science centers under the jurisdiction of the Federal Office of Defense Technology and Procurement. Its current tasks include technical investigations and testing of weapons, ammunition, armored vehicles and protective structures of all kinds. To this end, the extensive area in the Emsland region is used to conduct sprinkler tests on tanks, mine detection and medical vehicles, as well as on buildings. This naturally places special demands on the measurement technology used for this purpose.

 

In view of the reorientation of the Bundeswehr toward peacekeeping and peacekeeping "blue helmet" missions in crisis areas, the qualification and acceptance of the vehicles used there for mine protection is a particularly current task at WTD.

The possible effects on the occupants are examined. For this purpose, test dummies and seat structures are equipped with sensors to determine the forces and accelerations applied. The test dummies used are similar to the crash test dummies known from accident research, but are much more robust and even more elaborately designed.

The measured values can be used to calculate a so-called "Dynamic Response Index", which can be compared with ergonomic limit values. The metrological challenge in these tests lies in the extremely short duration of the processes and the large number of measurement data to be recorded simultaneously. The measurement duration is typically only 60 milliseconds, in exceptions sometimes up to 2 seconds. For example, 32 measurement channels with sampling rates of up to 1 MHz (corresponding to one million measurement values per second) are recorded per channel. Since the test objects are usually damaged after the test and the tests can therefore not be repeated, the greatest possible redundancy and data security of the measurements is required. The measuring instruments are located in a measuring container at a safe distance during the test, which requires complex sensor cabling of up to 100 meters in length.

With the LTT24, they have a measuring system that meets these high demands. This front-end system, developed and produced by LTT GmbH, the Würzburg-based specialist for ultra-fast measurement technology, expands the bandwidth of conventional PC measurement technology to previously unattainable dimensions. A single device offers 16 differential inputs. However, since the devices can be cascaded, synchronized acquisition of several hundred parallel channels is also possible. Separate A/D converters and amplifiers for each input allow simultaneous sampling of all channels and channel-specific amplification with input ranges between * 1 Volt and * 50 Volt. The possible sampling rate per channel ranges from 1 kHz to 2.5 MHz at 16 bits or up to 20 MHz at 12 bits, depending on the desired resolution. Each input has an adaptive anti-aliasing filter.

The measuring device itself does not require any drivers in the PC and is immediately ready for operation after being switched on. The internal hard disk of the device is automatically recognized by Windows as its own system drive and therefore allows direct access from the PC to the stored measurement data by any application programs.

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