Acoustic Properties of Additive Manufactured Porous Material

Acoustic porous materials are extensively used in many engineering applications like building, automobile, aviation, and marine. The health risk factor and environmental claims, associated with traditional materials such as glass wool, mineral fibers, and polymer foams demand for the alternative porous acoustic absorbing materials. Advances in additive manufacturing (AM) allow to manufacture complex structures and give an alternative method to produce porous materials. This study investigates the acoustic properties of porous sound-absorbing material produced by using additive manufacturing (AM) technique and explores the feasibility of AM to manufacture acoustic absorptive materials. For study, three samples with different aperture ratios were fabricated by AM technique, and their sound absorption coefficients were measured experimentally by using the impedance tube. The theoretical formulation for predicting normal sound absorption coefficient of sample with and without air gap was developed and compared with experimental results. The predicted absorption coefficient agrees well with measured results. The measured results indicate that the absorption coefficient of the structures fabricated through AM can be altered by varying aperture ratio and air gap behind the sample. This study reinforces the capability of AM for producing complex acoustic structures with better acoustic properties.