Abstract
Current research on the effectiveness of a subordinate oscillator array (SOA) as a broadband mechanical filter relies on adequate knowledge of the SOAs material properties. Recent studies have shown a high sensitivity of these structures to disorder. A desire to produce large numbers of arrays to test this sensitivity to disorder motivated a transition from metal to 3-dimensional printed plastic SOAs. Irregularities associated with the curing process of the 3D printed polymers, as well as a general inconsistency of material properties of plastics, in turn highlighted the need for characterization of properties of 3D printed materials, especially those properties related to damping. As part of this study, several 3D printed plastic cantilevers, varying in material, printing technique, and printing orientation, are measured. Quantities of interest include the Young’s modulus and density, as well as phenomenological properties, like the quality factor of specific designs. An ASTM standard test method for property determination is implemented with a laser Doppler vibrometer (LDV) to test each polymer. In addition to the ASTM protocol, tests are conducted in vacuum to distinguish internal damping mechanisms of the cantilever from external fluid mechanisms. Results are compared to both analytic and numeric predictions and published theory.
Highlights
Three-dimensional printing is increasing in popularity as new economical and efficient technologies are invented
The apparent damping effect publicized by Soize [4] and later observed by Strasberg and Feit [5] is being investigated at CUA through the design of subordinate structures that, once attached to a primary structure, transfer energy[6, 7]
If several subordinate elements are attached to a primary, each designed to have an isolated natural frequency within a range of frequencies surrounding the resonant frequency of the primary, the apparent dissipation of energy from the primary is broadened across the range
Summary
Three-dimensional printing is increasing in popularity as new economical and efficient technologies are invented. The apparent damping effect publicized by Soize [4] and later observed by Strasberg and Feit [5] is being investigated at CUA through the design of subordinate structures that, once attached to a primary structure, transfer energy[6, 7]. These subordinate structures are designed such that once the energy is transferred downscale away from the primary structure, it is dissipated in the subordinate array, essentially trapping the energy from the primary structure. The subordinate oscillators are referred to here as a subordinate oscillator array, or SOA
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