Design of continuously graded elastic acoustic cloaks

Journal Article · 25 January 2018 · Journal of the Acoustical Society of America

DOI: https://doi.org/10.1121/1.5019699 · OSTI ID:1464205

Sanders, Clay Michael ^[1]; Aquino, Wilkins ^[1]; Walsh, Timothy ^[2]

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1. Duke Univ., Durham, NC (United States)
2. Sandia National Lab. (SNL-NM), Albuquerque, NM (United States)

Here, this letter demonstrates the design of continuously graded elastic cylinders to achieve passive cloaking from harmonic acoustic excitation, both at single frequencies and over extended bandwidths. The constitutive parameters in a multilayered, constant-density cylinder are selected in a partial differential equation-constrained optimization problem, such that the residual between the pressure field from an unobstructed spreading wave in a fluid and the pressure field produced by the cylindrical inclusion is minimized. The radial variation in bulk modulus appears fundamental to the cloaking behavior, while the shear modulus distribution plays a secondary role. Such structures could be realized with functionally-graded elastic materials.

• Research Organization: Sandia National Lab. (SNL-NM), Albuquerque, NM (United States)
• Sponsoring Organization: USDOE National Nuclear Security Administration (NNSA)
• Grant/Contract Number: AC04-94AL85000
• OSTI ID: 1464205
• Report Number(s): SAND-2016-11393J; 649026
• Journal Information: Journal of the Acoustical Society of America, Vol. 143, Issue 1; ISSN 0001-4966
• Publisher: Acoustical Society of AmericaCopyright Statement
• Country of Publication: United States
• Language: English