Additive manufactured acoustic absorbers made of wood-fiber composites with modified infill patterns

The rapid urbanization and economic expansion have increased the negative consequences of environmental noise pollution. The sound that originates from various sources comes from distinct spectrums. To address the aforementioned issue, acoustic absorbers were 3D printed with varying infill patterns to absorb sound across a wide range of frequencies. Acoustic absorbers made of polylactic acid/polyhydroxyalkanoates-wood fibers (PLA/PHA-WF) were fabricated using Fused Deposition Modelling (FDM) technology, and their physical, mechanical, water absorption, biodegradation, and acoustic characteristics were measured and discussed. Acoustic absorbers printed with different infill patterns have a slight difference in density due to the size of the pores and the contact sites exhibited by the infill pattern. As a result, acoustic absorbers printed with varying infill patterns allow sound waves to enter and absorb sound at distinct spectrum levels. Modifying the infill pattern also had an effect on mechanical, water absorption, and biodegradation properties with minor deviations. The proposed biodegradable acoustic absorbers made of natural fiber composites and manufactured by FDM can be installed on building walls or roofs depending on the required acoustic absorption spectrum.