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Wave tailoring in granular chains
Wave tailoring in granular chains
Control of wave propagation is an area of active research, with applications in noise control, vibration reduction, acoustic switches and rectification, energy harvesting.
In this project, we designed a lattice of packed granules whose response under an impact load can be varied from rapidly decaying waves to a solitary wave. The lattice consists of elastic spheres packed into a hollow cylinder. By applying external pressure on the cylinder, the response of the lattice can be varied. The above figure illustrates this behavior, with a being the precompression level due to the external pressure. The lattice behavior changes due to the change in stiffness at the contact between two spherical granules.
Journal Publications:
- Tunable wave propagation in granular crystals by altering lattice network topology. ASME Journal of Engineering Materials and Technology , 2017. R. K. Pal, R. F. Waymel, P. H. Geubelle and J. Lambros.
- Wave tailoring by precompression in confined granular systems. Physical Review E, 2014. R. K. Pal and P. H. Geubelle.
Lattices with time-varying properties
Lattices with time-varying properties
Breaking time-reversal symmetry of an elastic structure allows for non-reciprocal or one-way wave propagation.
Journal Publication:
A Bloch-based procedure for dispersion analysis of lattices with periodic time-varying properties. Journal of Sound and Vibration, 2017. J. Vila, R. K. Pal, M. Ruzzene and G. Trainiti.
Defect nucleation in single crystals
Defect nucleation in single crystals
We conduct a critical examination of Schmid plasticity by investiagting defect nucleation in single crystal FCC and BCC metals at zero temperature using phonon stability analysis.
Contrary to widespread assumption, we found an abundance of short wavelength instabilities.
Journal Publication:
Non-Schmid effects and finite wavelength instabilities in single crystal metals. Extreme Mechanics Letters, 2018. H. Salahshoor, R. K. Pal and J. Rimoli.
Finite elements for fluid structure interaction
Finite elements for fluid structure interaction
In this project, we developed an algorithm to simulate fluid structure and free surface flow problems. The novel aspect involved a monolithic algorithm without any additional degrees of freedom at the interface.
Journal Publication:
A monolithic strategy for fluid structure interaction problems. International Journal for Numerical Methods in Engineering, 2011. C. S. Jog and R. K. Pal.
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