Research on Acoustic Absorption Properties of Aramid Honeycomb Composite Material Reinforced by Polyimide Foam

Abstract

To endue sound absorption behavior for aramid honeycomb core (ARHC), isocyanate‐based polyimide foam (IBPIF) with excellent thermal insulation and acoustic properties produced by a new formulation of foaming slurry is filled into ARHC by the free foaming route. As a core factor to adjust the cellular structure of IBPIF, the effect of water dosage on the acoustic behavior of IBPIF and IBPIF filled ARHC (IBPIF/ARHC) is studied, and the optimal formula to produce IBPIF/ARHC is filtered out. Results suggest that water dosage effectively regulates the cellular structure of IBPIF. When water dosage is 7.2 g, IBPIF has a large windows opening rate, which plays a positive role in sound absorption performance. IBPIF/ARHC‐3 has the best sound absorption property, which possesses a maximum sound absorption coefficient (α) of 0.9 at 1500 Hz. Its average α increases to 0.78 and shows an increase of 680% compared to ARHC. Meanwhile, the density of IBPIF/ARHC is only about 59 kg m−3. In 300–600 Hz range, IBPIF‐3 and ARHC show obvious synergy effects in sound absorption behavior. The average α of IBPIF‐3 and ARHC is only 0.3 and 0.06, respectively, and that of IBPIF/ARHC‐3 reaches up to 0.42. The thermal insulation performance of ARHC is also improved, and thermal conductivity decreases from 0.067 to 0.047–0.049 W (m K)−1.