Distorting an Impulse Wave with Phononic Metamaterials - a Scale Model Study

Bench-scale experiments were performed to characterize impulsive signal distortion with metamaterial arrays. Performing this task required the design of three unique elements: a low-cost, semi-anechoic chamber suitable for high frequencies; an in-lab tunable impulse source for both high frequencies and high amplitude; and a microphone array design for mapping the 3-D distortion of the impulse wave. The metamaterial arrays were achieved through the 3-D printed configurations of computer aided designs (CAD) extracted directly from a numerical model for exacting representations of configurations. A description of each component in the experiment and preliminary results are presented. Challenges presented by each of the components of the experimental design are also discussed. [The work described in this document was funded under the US Army Basic Research Program under PE 61102, Project T22, Task 01 "Military Engineering Basic Research"; Task 02 "Material Modeling for Force Protection" ; Project T25, Task 01 "Environmental Science Basic Research" and was managed and executed at the US Army ERDC.]