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Tuning acoustic impedance in load-bearing structures

Injeti, Sai Sharan and Celli, Paolo and Bhattacharya, Kaushik and Daraio, Chiara (2021) Tuning acoustic impedance in load-bearing structures. . (Unpublished) https://resolver.caltech.edu/CaltechAUTHORS:20210716-222546164

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Abstract

Acoustic transparency is the capability of a medium to transmit mechanical waves to adjacent media, without scattering. This characteristic can be achieved by carefully engineering the acoustic impedance of the medium -- a combination of wave speed and density, to match that of the surroundings. Owing to the strong correlation between acoustic wave speed and static stiffness, it is challenging to design acoustically transparent materials in a fluid, while maintaining their high structural rigidity. In this work, we propose a method to design architected lattices with independent control of the elastic wave speed at a chosen frequency, the mass density, and the static stiffness, along a chosen loading direction. We provide a sensitivity analysis to optimize these properties with respect to design parameters of the structure, that include localized masses at specific positions. We demonstrate the method on five different periodic, three dimensional lattices, to calculate bounds on the longitudinal wave speed as a function of their density and stiffness. We then perform experiments on 3-D printed structures, to validate our numerical simulations. The tools developed in this work can be used to design lightweight and stiff materials with optimized acoustic impedance for a plethora of applications, including ultrasound imaging, wave filtering and waveguiding.


Item Type:Report or Paper (Discussion Paper)
Related URLs:
URLURL TypeDescription
http://arxiv.org/abs/2106.10573arXivDiscussion Paper
ORCID:
AuthorORCID
Injeti, Sai Sharan0000-0003-1941-9752
Celli, Paolo0000-0001-7839-7472
Bhattacharya, Kaushik0000-0003-2908-5469
Daraio, Chiara0000-0001-5296-4440
Additional Information:This work was supported by the Shang-Li and Betty Huang endowed graduate fellowship fund in mechanical engineering at the California Institute of Technology. CD and PC acknowledge support from the National Science Foundation (NSF) CSSI grant number 1835735. We thank Lorenz Affentranger for helping us with the experimental setup.
Funders:
Funding AgencyGrant Number
Shang-Li and Betty Huang Fellowship, CaltechUNSPECIFIED
NSFOAC-1835735
Record Number:CaltechAUTHORS:20210716-222546164
Persistent URL:https://resolver.caltech.edu/CaltechAUTHORS:20210716-222546164
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:109892
Collection:CaltechAUTHORS
Deposited By: George Porter
Deposited On:16 Jul 2021 22:48
Last Modified:16 Jul 2021 22:48

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