Experimental/Numerical Acoustic Assessment of Aircraft Seat Headrests Based on Electrospun Mats

Abstract

The work proposes a methodology for the assessment of the performances of Passive Noise Control (PNC) for passenger aircraft headrests with the aim of enhancing acoustic comfort. Two PNC improvements of headrests were designed to reduce the Sound Pressure Level (SPL) at the passengers’ ears in an aircraft cabin during flight; the first was based on the optimization of the headrest shape, whereas the second consisted of partially or fully covering the headrest surface with a new highly sound-absorbing nanofibrous textile. An experimental validation campaign was conducted in a semi-anechoic chamber. A dummy headrest was assembled in different configurations of shape and materials to assess the acoustic performances associated to each set up. In parallel, simulations based on the Boundary Element Method (BEM) were performed for each configuration and an acceptable correlation between experimental and numerical results was obtained. Based on these findings, general guidelines were proposed for the acoustical design of advanced headrests.

Enhanced Low Frequency Sound Absorption of Bilayer Nanocomposite Acoustic Absorber Laminated with Microperforated Nanofiber Felt

“…From 0.17, the value increased to 0.33 as the nanofiber felt was introduced to the pure cryogel. Nanofibers’ high specific surface area promotes more collisions between the sound waves and the fibers boosting the consumption of acoustic energy as manifested in the absorption coefficient profile of the pure nanofibrous cryogel. ,,− We can verify from the SAC profile of a similar thickness of a commercial polyurethane (PU) foam that the use of nanofibers indeed boosts the acoustic performance of the sound absorbers. PU foam has a maximum coefficient of only 0.33 at 5000 Hz, which when compared to the cryogel shows very poor acoustic performance.…”

Active Noise Control for Aircraft Cabin Seats

“…A set-up consisting of a dummy seat with a headrest was equipped with two monitoring and error microphones and tested within a semi-anechoic chamber. Similar experimental conditions were also investigated in [25] to assess the acoustic performance of two passive noise control concepts based on either a tailored headrest shape or an innovative nanofibrous textile material. The receiving room was a semi-anechoic chamber with dimensions of 6.5 × 5.3 × 4.2 m (volume 145 m 3 ) and a cut-off frequency of 70 Hz.…”

“…This technology is being developed and validated up to Technological Readiness Level (TRL) 4 through dedicated experimental campaigns performed at the component level. Numerical assessments are also envisaged at a full-scale level for a digital aero-vibroacoustic model of an actual aircraft cabin, including the modeling of both the external disturbances and the primary and secondary components [25][26][27].…”

Advances in Vibroacoustics and Aeroacustics of Marine, Aerospace and Automotive Systems

“…The work proposed in [8] reported a further simulation investigation based on BEM to perform passive noise control (PNC) assessments for passenger aircraft headrests. In particular, two PNC improvements of headrests were designed to reduce the sound pressure level (SPL) at the passengers' ears in an aircraft cabin during flight; the first was based on the optimization of the headrest shape, whereas the second consisted of partially or fully covering the headrest surface with a new highly sound-absorbing nanofibrous textile.…”