Acoustic Properties of 3D Printed Bulk Absorbers with Novel Surface Topologies

"font-size: 12px;">Traditional manufacturing techniques offer limited control over the cellular architecture of porous materials and often do not allow fabrication of complex topologies. Here, we utilize 3D printing to overcome these difficulties and fabricate bulk absorbers with novel cellular architectures for use as acoustic liners. Absorbers with controlled surface topologies were fabricated using a combination of a commercial mathematical plotting software (MATLAB) and stereolithographic (SLA) 3D printing. The developed MATLAB tool generates porous architectures using a field of points defined by a 3D grid and allows precise control over all microstructural parameters. The generated structures are then converted into the native STL file format required for 3D printing using commercial 3D printers. The acoustic properties of the fabricated bulk absorbers were measured using a normal incidence tube setup. The effects of surface geometry, pore size, and through-thickness density gradients on the acoustic properties of the absorbers are studied and compared with equivalent-fluid model predictions.