Fabrication and optimization of acoustic properties of natural fiber reinforced composites

Natural fiber reinforced composites (NFRC) are in great demand for sound absorption applications in various industries, such as automotive, aircraft, and building construction applications compared to synthetic composite materials. Though conventional sound-absorbing materials are used for passive control, natural fibers are more effective and economical for sound-absorption treatments. This paper presents the efforts made in the preparation of various NFRC made of flax, hemp, and kenaf fibers with epoxy as a matrix material. Also, the acoustic properties of the natural fiber-reinforced composites are studied by measuring the sound absorption coefficient (SAC). The experiments were conducted to measure the SAC of composite samples of different thicknesses by using the impedance tube method with the aid of Active Format Description 1001 (AFD 1001) software at frequencies ranging from about 200 to 1600 Hz. Moreover, the combined effects of various natural fiber composites were studied by conducting detailed experimentation. The experimental results show that the flax fiber composite possesses a higher SAC ranging from about 0.778 to 0.892 varying the test specimen thickness from 20 to 40 mm. From the results, the flax composite has a high sound absorption coefficient compared to hemp and kenaf composites. The optimization of Acoustic properties was carried out by using an Analysis of Variance and the influence of factors such as type of composite material and composite thickness on SAC was calculated.