WP1 activities have simulated and virtually demonstrated the operational performance of a vibration control system to a full-scale aircraft, in order to achieve substantial reduction in its fuselage Acoustic Pressure. The target of reduction was set to 15 dB, the target frequency was the N1=110 Hz and the anti-vibration setup was a lab-scale demonstrator presented in D1.5 at the University of Patras. Concerning the installation parameters of the anti-vibration setup, a commercially available piezoelectric actuator was proposed (see D1.6) with minimal effect on the mount stiffness. The installation of each actuator was simulated to be parallel to the existing mount and the total weight of the anti-vibration system (actuators plus amplifiers) for each investigated case does not exceed 16 kg. Conclusively, the working procedure was presented to reach and overcome the target reduction of 15 dB in the fuselage Acoustic Pressure, by using a minimum number of actuators. Installation of the proposed system had slight effect on the existing mount stiffness, and operated with almost negligible power requirements.
In WP2, An ANC system has been designed and integrated inside each passenger seat, consisting of loudspeakers, microphones and control law device. The integrated ANC system has been implemented and experimentally tested in a two face-to-face three passenger seat configuration, inside a cabin mock-up. The ANC system is based on a conventional FxLMS algorithm for reliability and simplicity reasons and it has been tested through different noise signals, aiming to a local adaptive noise cancellation and can successfully:
• Reduce the overall noise level of noise up to 23 dB at the nominal ear position D.
• Reduce the spectrum peak amplitude of noise up to 20 dB at the nominal ear position D.
• The proposed spatial H/W arrangement (microphones and loudspeakers) of the ANCS achieves significant performance of ANC system building a quiet zone far away from the error microphone and close to a desired location (passenger’s ear). So, it is not important the error microphone to be placed closed to the ear in order the zone of quietness to be achieved in the vicinity of it.
• The random background noise does not show a remarkable change.
• The total weight of the H/W (FPGA controller, microphones, loudspeaker, amplifiers and power supply) is less than 9 Kg.
It is therefore concluded that the system can successfully meet the project requirements, i.e. to offer at least a 10 dB reduction at the engine rotation speed. Moreover, the system offers the potential for an overall 15 dB noise reduction under specific conditions. Finally, the overall weight of the system does not exceed 9Kg.
In WP3, the procedure followed was to model the full-scale aircraft in accordance with the input provided by DA, to validate that and to construct a coupled aircraft-SATMD model capable to tune at different frequencies. Finally, the proposed system performance was presented on the aircraft full scale model and multiple scenarios were presented. Two tuning cases were used and were also both commercial actuators and customized. Relative to the proposed SATMD scenarios the main conclusions are:
1. When using commercially available actuators, the required auxiliary mass exceeds the provided wight limitations for attempting a reduced behavior. This is due to the actuator’s stiffness restricting us from freely tuning the SATMD initially to the targeted mode. Also, the piezoelectric stack is not optimized and when tuned on lower modes the performance is not optimal, however with a higher auxiliary mass it achieves reductions up to 6 dB.
2. Custom actuators performance achieves higher reductions since we can tune the SATMD on the target mode using auxiliary mass within the weight limitation. Also, piezoelectric stack is optimized thus achieving higher performance when tuned on lower modes similar to the ones of the previous scenario decreasing also the mas
