Combining transformation physics and homogenization for designs of seismic cloaks, by Lucas Pomot (Aix Marseille University)

DENORMS Action’s Workshop “Modelling of high performance acoustic structures Porous media, metamaterials and sonic crystals”, Rome, 24-25th January 2017

Website of DENORMS Action

Programme of the Workshop

Session on New trends in vibroacoustics (i.e. elastic metamaterials and metasurfaces)

Speaker: Lucas Pomot (Aix Marseille University)

Abstract:

The concept of cloaking appeared in electromagnetism with the goal to make objects invisible inside a wave field. Cloaking consists of a geometric transformation of the medium, which forces an incident wave to get around a given ‘invisibility’ region. So far, many applications in various fields were studied leading to a large amount of theories and experiments. The present study aims at creating an invisibility cloak for Lamb waves both at a theoretical and an experimental level. The theory is based on homogenization techniques: by introducing small perturbations in the propagative medium we are able to create a controlled anisotropic structured material. The propagative medium studied here is an aluminium thin-plate. The perturbations are created with small see-through holes (stress-free inclusions in the plate). These results will be extended to surface waves , as a step towards an invisibility cloak for ground vibrations and seismic waves with the possibility to reduce the noise inside buildings or to isolate strategic civil engineering structures from earthquakes.