Vibration measurements by means of IPCT

Abstract

Within AIM (Advanced In flight Measurement technique) European research framework, one of the subtasks was related to the evaluation of the possibility to measure structure vibration by means of IPCT on a small aircraft. This kind of task has been already successfully attempted; this case novelty is that the attempt has been done in an industrial environment on a small aircraft, with an unsuitable shape, which is busy all the time for testing related to production. So this testing activity was inserted inside and performed like a normal all day’s experimental activity. Due to budget reasons it was decided at first to do it on ground, simulating flight conditions, measuring wing vibration. Taking advantage of the test set up prepared for static deformation measurement; some vibration measurement have been performed also in flight. On ground a set of accelerometers were installed in order to compare IPCT results with those obtained with traditional means; an exciter was placed at the wing tip driven by a PC which generated a signal at the desired frequency, hence a frequency sweep was performed around the known natural frequencies (actually exciting the first wing bending mode). Accelerometers were also installed on the camera support in order to evaluate if the camera itself was vibrating.