Acoustic Wave Management
Repeated exposure to nonlethal blast-induced pressure waves can result in traumatic long-term injuries even in the absence of overpressure and visible tissue damage. The basic physical mechanisms of this phenomenon need to be identified, understood, and quantified. In particular, we need to understand and quantify the interaction between acoustic waves and brain tissues and the frequency ranges that result in long-term neurological injury. Concurrently, we need to design and produce light-weight materials with suitable microstructures that can be used to cloak the brain against harmful blast-induced acoustic waves.
Material anisotropy can split and redirect acoustic stress waves around a target object and then re-combine them on the opposite side of the object to produce waves that have their original spatial distribution, although they may be partially attenuated. This makes the object seem invisible or protected from the impinging stress waves.
Selected Paper: Stress-wave energy management through material anisotropy. A.V. Amirkhizi, A. Tehranian and S. Nemt-Nasser, Wave Motion,[18 pages- in-press] 2010.