Medium-and-low-frequency light-and-thin sound insulation and absorption panel, and composite wallboard thereof

A medium-and-low-frequency light-and-thin sound insulation and absorption panel, consisting of a plurality of units arranged in parallel; each unit consists of a rigid framework, an elastic thin film and a perforated panel having a through hole; the elastic thin film is connected to the rigid framework, and the perforated panel is connected to the elastic thin film; two sound insulation and absorption panels with one layer of sound absorption layer clamped therebetween form a sound insulation and absorption composite panel, such that a near field wave generated by the sound insulation and absorption panels passes back and forth through the sound absorption layer to effectively dissipate the sound energy, thus improving sound wave insulating effect; the composition panel, a heat insulation and sound absorption layer and a casing are sequentially connected from inside to outside to form a sound and heat insulating composite wallboard. The sound insulation and absorption panel, the composite panel and the composite wallboard have good sound insulating effect across the low-and-medium frequency domain; and a composite panel having a thickness of 10 mm and an areal density of 1.5 kg/m 2 added to the casing increases the sound insulation by about 25 dB in a designed frequency range. The present invention is suitable to serve as the cabin wallboard of airplanes, spacecraft, automobiles, trains and ships.