Computational material design for acoustic cloaking

GUSTAVO MÉNDEZ, CARLOS; PODESTÁ, JUAN MANUEL; LLOBERAS-VALLS, ORIOL; TORO, SEBASTIÁN; HUESPE, ALFREDO EDMUNDO; OLIVER, JAVIER

INTERNATIONAL JOURNAL FOR NUMERICAL METHODS IN ENGINEERING

JOHN WILEY & SONS LTD

Año: 2017 vol. 112 p. 1353 - 1380

0029-5981

p { margin-bottom: 0.1in; line-height: 120%; }a:link { }A topologyoptimization technique based on the topological derivative and thelevel set function is utilized to design/synthesize themicrostructure of a pentamode material for an acoustic cloakingdevice. The technique provides a microstructure consisting of ahoneycomb lattice composed of needle-like and joint members. Theresulting metamaterial shows a highly anisotropic elastic responsewith effective properties displaying a ratio between bulk and shearmoduli of almost three orders of magnitude. Furthermore, inaccordance with previous works in the literature, it can be assertedthat this kind of microstructure can be realistically fabricated.The adoption of a topology optimization technique as a tool for theinverse design of metamaterials with applications to acousticcloaking problems is one contribution of this paper. However, themost important achievement refers to the analysis and discussionrevealing the key role of the external shape of the prescribeddomain where the optimization problem is posed. The efficiency of thedesigned microstructure is measured by comparing the scattering wavefields generated by acoustic plane waves impinging on bare andcloaked bodies.