@article{gerard_oudich_xu_yao_cui_naify_ikei_rohde_zheng_jing_2021, title={Three-Dimensional Trampolinelike Behavior in an Ultralight Elastic Metamaterial}, volume={16}, ISSN={["2331-7019"]}, url={https://doi.org/10.1103/PhysRevApplied.16.024015}, DOI={10.1103/PhysRevApplied.16.024015}, abstractNote={Elastic metamaterials possess band gaps, or frequency ranges that are forbidden to wave propagation. Existing solutions for impeding three-dimensional (3D) wave propagation largely rest on high-volume fractions of mass inclusions that induce and tailor negative effective density-based local resonances. This study introduces a class of elastic metamaterials that achieve low-frequency band gaps with a volume fraction as low as 3% (mass density as low as $0.034\phantom{\rule{0.1em}{0ex}}\mathrm{g}/{\mathrm{cm}}^{3}$). The working of the proposed design hinges on a 3D trampolinelike mode behavior that gives rise to wide, omnidirectional, and low-frequency band gaps for elastic waves despite very low-mass densities. Such a 3D trampoline effect is derived from a network of overhanging nodal microarchitectures that act as locally resonating elements, which give rise to band gaps at low frequencies. The dynamic effective properties of the metamaterial are numerically examined, which reveal that the band gap associated with the trampoline effect is resulted from a negative effective modulus coupled with a near-zero yet positive effective density. The experimental characterization is then made possible by fabricating the metamaterial via a light-based printing system that is capable of realizing microarchitectures with overhanging microfeatures. This design strategy could be useful to applications where simultaneous light weight and vibration control is desired.}, number={2}, journal={PHYSICAL REVIEW APPLIED}, author={Gerard, Nikhil Jrk and Oudich, Mourad and Xu, Zhenpeng and Yao, Desheng and Cui, Huachen and Naify, Christina J. and Ikei, Alec and Rohde, Charles A. and Zheng, Xiaoyu and Jing, Yun}, year={2021}, month={Aug} }
 @article{xu_hensleigh_gerard_cui_oudich_chen_jing_zheng_2021, title={Vat photopolymerization of fly-like, complex micro-architectures with dissolvable supports}, volume={47}, ISSN={["2214-7810"]}, DOI={10.1016/j.addma.2021.102321}, abstractNote={Recent advances in additive manufacturing of complex geometries enabled the creation of mechanical metamaterials whose exotic properties are based on local control of complex cell geometries. Overhanging and free-hanging features that lack continuous support layers in the previous build volume cannot be directly manufactured, imposing a major design limitation. The resulting metamaterials are limited to single homogenous structural materials, and inherently self-supporting geometries, resulting in constraints of achievable architectures. Realizing arbitrary features is compelling but is inherently limited by process and material support constraints. Here we present a novel light-based additive manufacturing approach capable of printing arbitrary micro-architectures comprising a large array of internally suspended features, large span overhang, and high aspect ratio struts. This method eliminates the need for manual removal of internal supports and enables a suite of multi-functional metamaterials with a range of designed properties, including wide bandgaps for elastic waves at low frequency, switchable wave transmissions, and products requiring no post support removal. We describe the synthesis and rapid printing of a variety of metamaterials comprising an extensive array of suspended features and demonstrate their metamaterial behaviors. The proposed approach removes scale and unit cell limitations and is capable of achieving embedded features across multiple materials.}, journal={ADDITIVE MANUFACTURING}, author={Xu, Zhenpeng and Hensleigh, Ryan and Gerard, Nikhil J. R. K. and Cui, Huachen and Oudich, Mourad and Chen, Wentao and Jing, Yun and Zheng, Xiaoyu}, year={2021}, month={Nov} }
 @article{wu_oudich_cao_jiang_zhang_ke_yang_deng_cheng_cui_et al._2019, title={Routing Acoustic Waves via a Metamaterial with Extreme Anisotropy}, volume={12}, ISSN={["2331-7019"]}, DOI={10.1103/PhysRevApplied.12.044011}, abstractNote={Routing acoustic waves without backscattering losses is presently of great interest. Unlike both conventional approaches using defects in sonic crystals and emerging approaches based on topological edge states, this study proposes a radically different theoretical framework that utilizes extremely anisotropic media to engineer backscattering-immune waveguides. The exact condition for one-way wave propagation along zigzag paths is derived. The proposal is experimentally validated using spoof surface acoustic waves, and the results could have implications for on-chip wave manipulation, as well as noise control.}, number={4}, journal={PHYSICAL REVIEW APPLIED}, author={Wu, Liting and Oudich, Mourad and Cao, Wenkang and Jiang, Haolin and Zhang, Cheng and Ke, Junchen and Yang, Jin and Deng, Yuanchen and Cheng, Qiang and Cui, Tiejun and et al.}, year={2019}, month={Oct} }