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Seminar - "Computational material design for acoustic cloaking", by Alfredo Huespe

Tuesday, February 7th, 2017. Time: 12 h.

Place: O.C. Zienkiewicz Conference Room, C1 Building, UPC Campus Nord, Barcelona.

ABSTRACT

Acoustic cloaking makes invisible an object to sound waves impinging on it in any direction. This effect can be achieved through passive devices by covering the object with an appropriately designed layer of material having extreme and highly anisotropic elastic properties. Nowadays, metamaterials having these properties can be designed and manufactured.

A possible way to reach this objective, and realize this idea, is appealing to transformation acoustic, as a mathematical tool to define the mechanical and acoustical properties that the layer should display in every point of the space, plus material design techniques searching for a microstructure depicting these target properties.

First, in this talk, we present a very general overview of transformation acoustic as an application to acoustic cloaking and possible kinds of materials that have been proposed for solving this problem. Emphasis is been given to pentamode materials.

In the second part, we describe a topology optimization technique based on the topological derivative and the level set function that can be utilized to synthesize the micro-structure of a pentamode material useful for an acoustic cloaking device. The so-obtained metamaterial shows a highly anisotropic elastic response with effective properties displaying a ratio between bulk and shear moduli of almost 3 orders of magnitude.

SPEAKER CV

Dr. Alfredo E. Huespe is Mechanical Engineer by the National University of Cordoba, Argentina and Ph.D. by Federal University of Rio de Janeiro, Brazil. Since 1998, he is Researcher at Conicet, Argentina and Professor at the National University of Litoral, Argentina. Since 2010, he is Associate Professor at the Technical University of Catolonia, Spain. In 2003, he has been a Ramon y Cajal Research Fellow at the Technical University of Catolonia. In 2007, he has been a Fulbrigth-Conicet Fellow at Brown University, USA. He is a visiting scientist at CIMNE and his specific areas of interest include computational solid mechanics, computational failure mechanics, fracture mechanics, finite elements for plasticity and damage models, and strain localization phenomenon. More recently he has been researching in the field of material design.