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Exploiting pattern transformation to tune phononic band gaps in a two-dimensional granular crystal
F Göncü1, S Luding, K Bertoldi
1Multiscale Mechanics, University of Twente, P.O. Box 217, 7500 AE Enschede, The Netherlands. f.goncu@utwente.nl
The Journal of the Acoustical Society of America
|June 21, 2012
Summary
The band structure of 2D granular crystals is tunable via mechanical compression, which alters their pattern. This transformation, not particle type, dictates changes in band gaps and overall crystal behavior.
Area of Science:
- Materials Science
- Condensed Matter Physics
- Acoustic Metamaterials
Background:
- Two-dimensional granular crystals exhibit pattern transformation under uniaxial compression.
- Previous work by Göncü et al. (2011) demonstrated this phenomenon in silicone rubber and polytetrafluoroethylene (PTFE) cylinders.
Purpose of the Study:
- To numerically investigate the band structure of a 2D granular crystal composed of silicone rubber and PTFE cylinders.
- To demonstrate the tunability of the band structure through mechanical deformation and induced pattern transformation.
- To elucidate the role of pattern transformation versus particle mechanical properties in governing band structure changes.
Main Methods:
- Numerical computation of dispersion relations for the granular crystal.
- Analysis of band structure at various levels of uniaxial compression.
- Comparative study involving replacement of PTFE particles with rubber particles.
Main Results:
- The band structure is significantly tunable with applied deformation.
- Uniaxial compression induces a pattern transformation, leading to the emergence of new band gaps.
- Band structure modifications are primarily driven by the pattern transformation, irrespective of the constituent particle materials.
Conclusions:
- The mechanical deformation of 2D granular crystals offers a pathway to tune their band structure.
- Pattern transformation is the dominant mechanism controlling band gap formation and tunability.
- The findings highlight the importance of mechanical design in creating tunable acoustic or phononic materials.
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