Title: Experimental noise and vibration analysis in an aircraft simplified hydraulic systems
text: Due to the great use of airplanes for transportation, it was necessary some studies to improve it, one of the most difficult problems to solve, is the noise generated by the systems. In-flight sound pressure levels can sometimes be intense and cause fatigue to the cabin crew, communication failures and discomfort to the passengers. This is often caused by the turbulent boundary layer over the aircraft body, engine noise and vibration and internal aircraft systems. The aircraft hydraulic system is responsible for moving the rudder, aileron, brakes, main door, and other components, and consequently, the noise of this system became more noticeable. This system comprises a pump, generally, located at the back of the aircraft and pipes, which are fixed along the fuselage. The pipes are connected to the fuselage using rubber mounts. Analyzing experimental measurements is possible to identify that hydraulic system contribute to the in-flight sound pressure level in the aircraft cabin. However is the connection between pipe and fuselage the main problem. In this paper, will be demonstrated a simplified methodology to analyze these noise, generated by the hydraulic system, with results of sound pressure and vibration measured in an experimental device, operated under different conditions.