Vibroacoustic behavior and noise control of flax fiber-reinforced polypropylene composites

Driven by the need for sustainable eco-friendly materials, natural fibers are increasingly being used as composites reinforcements due to their low cost and their potential in meeting strength and stiffness requirements for nonstructural and semistructural applications. Fewer works, however, have been reported on the acoustic and vibration characteristics of natural fibers. In this article, the sound transmission and absorption performance of flax fiber-reinforced polypropylene (PP) composites in various configurations are assessed experimentally. Natural frequency and damping coefficient of the composites are investigated by modal analysis with an impact hammer. Results from the vibrational analysis showed that thin FF/PP composite panels have resonant frequency ranging between 300 and 1000 Hz which is consistent with the acoustic profile extracted from the sound transmission loss (STL) test. Results of STL tests revealed that higher stiffness of FF/PP composite may lead to higher STL at 100-400 Hz. Resonant frequencies of the composite range from 400 to 900 Hz and STL is show to obey the mass law with nonlinearity in the range of 900-1600 Hz. These results give a better insight into the performance of FF/PP composites in vibroacoustic environments.