Highly strained mixtures of bidimensional soft and rigid grains: an experimental approach from the local scale

TL;DR

This experimental study investigates the mechanical behavior of 2D mixtures of soft and rigid grains under compression, revealing unique jamming characteristics and system evolution at high packing fractions, advancing understanding of polydisperse granular materials.

Contribution

First experimental analysis of highly strained 2D mixtures of soft and rigid grains, providing insights into their jamming transition and internal mechanical behavior.

Findings

Detected the jamming transition from internal observables.

Analyzed the evolution of the system deep in the jammed state.

Identified unique behaviors compared to purely soft or rigid systems.

Abstract

Granular systems are not always homogeneous and can be composed of grains with very different mechanical properties. To improve our understanding of the behavior of real granular systems, in this experimental study, we compress 2D bidisperse systems made of both soft and rigid grains. By means of a recently developed experimental set-up, \md{from the measurement of the displacement field we can} follow all the mechanical observables of this granular medium from the inside of each particle up-to-the whole system scale. We \md{are able to} detect the jamming transition from these observables and study their evolution deep in the jammed state for packing fractions as high as $0.915$. We show the uniqueness of the behavior of such a system, \md{in which way} it is similar to purely soft or rigid systems and how it is different from them. This study constitutes the first step toward a better understanding of the mechanical behavior of granular materials that are polydisperse in terms of grain rheology.