Smart carbon-epoxy laminate with high dissipation properties for vibro-acoustic optimization in the turboprop aircraft

The transport industry especially that aviation one is investing in research for innovative technologies to improve the internal comfort both in the design phase and in aircraft already operative. The vibration and noise attenuation is of course among the most relevant target in the aeronautical scientific community actually many research programs which see the cooperation between academic institutions and leading industries are promoting the development and the application of innovative materials: smart composites, SMA, piezoceramics are only few examples of this increasingly emerging field. In this paper, the latest results achieved on the self-healing laminates for their too very appreciable damping performance are presented. The effectiveness of the proposed biomimetic technology has already been assessed in terms of damping capability compared to a standard CFRC specimen. The tests evidence has revealed a really better behavior of the self-healing sample compared to the conventional one in terms of vibrational energy: the average damping coefficient, measured in two different ways has been found to be about four times higher. Therefore, relying upon the results achieved on simple specimens, a numerical model representative of an aircraft fuselage section has been developed in order to predict the levels of noise and vibrations generated by a typical propeller excitation load. A careful investigation of air-structure interaction for internal noise forecast and surface radiated power has been carried out combining the numerical solutions performed within MSC Nastran® and Actran® environments. The Finite Element approach has allowed for emphasizing that the adoption of these smart treatments could led to an average noise reduction of about 3 dB compared to the conventional laminate configuration as well as a surface vibration decrease up to 50%.