109 research outputs found
An innovative wide and low-frequency bandgap metastructure for vibration isolation
No full textEngineering the architecture of materials is a new and very promising approach to obtain vibration isolation properties. The biggest challenge for lattice structures exhibiting vibration isolation properties is the trade-off between compactness and wide and low-frequency bandgaps, i.e., frequency ranges where the propagation of elastic or acoustic waves is prohibited. Here, we, both numerically and experimentally, propose and demonstrate a new design concept for compact metamaterials exhibiting extraordinary properties in terms of wide and low frequency bandgap and structural characteristics. With its 4 cm side length unit cell, its bandgap opening frequency of 1478 Hz, its band-stop filter behavior in the range 1.48-15.24 kHz, and its structural characteristics, the proposed 1 x 1 x 3 metastructure represents great progress in the field of vibration isolation and a very promising solution for hand-held vibration probes applications that were unattainable so far through conventional materials
A compact 3D bandgap multi-material metamaterial design for vibration testing
No full textThe use of metamaterials is an established approach in the field of vibration isolation, leveraging their exceptional tunability over a vast range of frequencies. A key challenge in designing lattice structures is the trade-off between geometrical compactness and wideness of the bandgap, i.e. the frequency range in which wave propagation is not allowed. A possible solution to reduce the size of the structure while maintaining or improving its vibrational performances, is to incorporate different materials in the metamaterial design. In this paper, we present a compact metamaterial, whose design is driven by a multi-material approach, that exhibits extraordinary properties in terms of wide frequency bandgap and lower frequency threshold. The vibrational performance of the proposed metamaterial is validated both numerically and experimentally for a unit cell with a side length of 3 cm. The results show a bandgap opening frequency of 1257 Hz and a low pass filter behavior in the range 1.2..
Importanza delle metodiche non invasive in un programma di screening e follow up delle malattie della mammella
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Damage control surgery for the treatment of perforated acute colonic diverticulitis: A systematic review
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Dermoscopy of annular lichenoid dermatitis of youth (ALDY): An observational controlled study
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