Novel Libri GmbH Novel Materials for Sound-Absorbing Applications

The Reprint contains eight papers devoted to the topic of sound-absorbing materials. These papers analyze the sound absorption of new materials, both in terms of raw materials and their structure and form. The presented research indicates the potential for using rubber granulate from automotive recycling in both loose granular and compacted forms, mineral diatomite in powdered form as a filler for fibrous thermoplastic composites, and tannery wool waste used to create the underlayment of tufted carpets, among other things, to construct acoustic barriers. The potential of these materials is related to determining their optimal fraction and optimal percentage in the final products.Furthermore, the research focuses on the development of new acoustic absorber structures, including those with a controlled resonance frequency and a tunable acoustic absorption band, which indicates progress in the design of adjustable acoustic absorbers. New methodologies for estimating and determining the sound-absorbing properties of materials with complex, sophisticated structures, such as foam, honeycomb (Helmholtz-type metamaterial), hybrid (membrane metamaterial consisting of an aluminum membrane connected to piezoelectric patches and an air cavity), and powder materials, were presented.