We report the combined results of both experiments and molecular dynamics simulations, carried out to investigate superheating phenomena in vertically vibrated granular matter. Specifically, we consider a system of cubic particles, densely packed in a squared-lattice array and subjected to different acceleration shaking strengths $\mathrm{\Gamma }$. Below a critical value ${\mathrm{\Gamma }}_c\sim 3.2$, the excited crystalline array remains stable indefinitely, whereas for a fixed $\mathrm{\Gamma }>{\mathrm{\Gamma }}_c$, the system stays first in a metastable solid phase and then it transitions progressively into a liquid phase, during a $\mathrm{\Gamma }$-dependent timescale ${\tau }_m$. The value of ${\mathrm{\Gamma }}_c$ required to observe metastable superheated states for cubic particles is considerably larger than the value previously reported for spherical beads (${\mathrm{\Gamma }}_c^{\text{sph}}\sim 1.4)$, which is attributed to a more efficient energy dissipation process due to interparticle friction, that also lengthens substantially the lifetime of the superheated crystal. Notably, however, the exponents of the power scaling laws for ${\tau }_m\left(\mathrm{\Gamma }\right)$ are very similar for both geometries, suggesting universality in this transition. Our findings also show that the transition from the superheated-solid to the liquid state of the vibrated system is well captured by a Kolmogorov-Johnson-Mehl-Avrami equation, routinely employed to describe phase transformations in thermal systems.

Close

PrevNext

View figure in article

• Applications of soft matter
• Classical statistical mechanics
• Collective behavior
• Crystal melting
• Granular packing
• Nonequilibrium statistical mechanics
• Phase behavior
• Phase transitions
• Granular materials
• Granular solids