Plasticity in granular media
This project investigated plastic dissipation in granular media due to impact loads for potential stress wave tailoring and impact protection applications.
Consider a block of steel and a granular packing of steel. Due to geometry (spheres vs a bulk block), we expect the impact response to be very distinct. My PhD thesis quantified this difference.
The videos show impact on an elasto-plastic continuous solid half-space and on a granular packing made of the same material. The size of the plastic zone (indicated in red) is localized near the impactor in the first case, while it spreads over a large volume in the granular case.
Similarly, the energy dissipated is also significantly higher in the granular case. These differences arise due to stress concentration at the point contacts in granular media, thereby illustrating their potential for superior stress wave protection capability.
Journal Publications
- High-amplitude elastic solitary wave propagation in 1-D granular chains with preconditioned beads: Experiments and theoretical analysis. Journal of the Mechanics and Physics of Solids, 2014. E. Wang, M. Manjunath, A. Awasthi, R. K. Pal, P. H. Geubelle and J. Lambros.
- Impact response of elasto-plastic granular and continuum media: A comparative study. Mechanics of Materials, 2014. R. K. Pal and P. H. Geubelle.
- Characterization of wave propagation in elastic and elastoplastic granular chains. Physical Review E, 2014. R. K. Pal, A. Awasthi and P. H. Geubelle.
- Impact response of elasto-plastic granular chains containing an intruder particle. Journal of Applied Mechanics, 2015. R. K. Pal, J. Morton, E. Wang, J. Lambros and P. H. Geubelle.
- Wave propagation in elastic and elastoplastic granular systems. Granular matter, 2013. R. K. Pal, A. Awasthi and P. H. Geubelle.