Bulletin of the American Physical Society
APS March Meeting 2018
Monday–Friday, March 5–9, 2018; Los Angeles, California
Session F48: Mechanical Metamaterials II
11:15 AM–2:15 PM,
Tuesday, March 6, 2018
LACC Room: 510
Sponsoring Units: GSNP GSOFT DBIO DPOLY
Chair: Sung Kang, Johns Hopkins Univ
Abstract: F48.00003 : Quasistatic, Dynamic and Acoustic Characteristics of Microlattice Metamaterials*
11:39 AM–11:51 AM
(Mechanical and Civil Engineering, California Institute of Technology)
The quasistatic, dynamic (strain rate~1000/s) and acoustic characteristics of ultrathin and highly porous microlattice metamaterials were investigated. The 3-D microlattice architectures were systematically varied in such a way that bending deformation increasingly dominated, so that the Poisson’s ratio of the microlattices transitioned from positive to negative. Under quasistatic testing, this auxetic behaviour was found to improve the energy absorption properties of the microlattices, but played a much lesser role during dynamic compression tests, due to the onset of a secondary buckling mode which nullified the auxetic behaviour. In addition, it was also found that auxetic microlattices were able to significantly reduce the transmission of ultrasonic waves over an extended frequency range when compared to non-auxetic designs. Numerical computations suggest that the bending deformation of the auxetic microlattices introduced different mode shapes for the propagation of elastoacoustic waves. The insights derived from these studies are expected to contribute to the design of microlattice metamaterials with novel properties, such as ultrahigh impact/ acoustic energy absorption efficiency.
*Temasek Research Fellowship and the Swiss National Science Foundation, Grant Number SNF164375.
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