Material Parameter Identification for Acoustic Simulation of Additively Manufactured Structures

Area of Science:

• Additive Manufacturing
• Acoustics
• Materials Science

Background:

• Additive manufacturing offers design freedom for complex structures.
• Acoustic Black Holes (ABH) utilize layer-wise material deposition for tunable mechanical impedance.
• Homogenized material parameters in AM structures depend on process parameters and geometry.

Purpose of the Study:

• To experimentally and numerically investigate material parameters of polyactic acid (PLA) beams.
• To identify the dependency of these parameters on frequency and thickness for ABH applications.
• To develop reliable mechanical models for AM-based acoustic designs.

Main Methods:

• Fabrication of PLA beams with varying thicknesses.
• Experimental testing and numerical simulations using a 3D finite element model.
• Parameter fitting with a reduced-order Krylov subspace model.

Main Results:

• Homogenized material parameters for PLA were determined as a function of frequency and thickness.
• An increasing Young's modulus was observed with increasing frequency and thickness.
• This thickness and frequency dependency significantly impacts acoustic performance.

Conclusions:

• The identified material parameters provide a more accurate representation of PLA behavior in AM structures.
• This research enables more reliable design and simulation of acoustic devices, particularly ABH.
• The findings highlight the importance of considering thickness and frequency dependencies in AM material characterization.