In-flight measurement of acoustic background noise for the development of impact detection algorithms

摘要

A fighter aircraft has been instrumented with piezo sensors on a carbon fibre reinforced plastic main landing gear door. During ground handling and standard test flights, the piezo sensor output was recorded on a flight test instrumentation tape recorder with a frequency range from 30 kHz to 250 kHz. Parallel to the flight test, a number of laboratory impact tests have been performed on a separate CFRP main undercarriage door with the same sensor suite. The measured background noise level has been compared to the impact spectra from the laboratory tests. The comparison shows at least a difference of 30 dB between the impact and the background noise.