Jamming by shear in a dilating granular system

Jamming can occur in frictional granular materials undergoing shear at a fixed packing fraction, ϕ, within a range below the isotropic jamming point, with the amount of strain required to induce jamming, γ, increasing with decreasing ϕ. We are interested in how the shear jamming process is affected when the system dilates as it is sheared. We conduct experiments to shear a 2D granular system while continuously increasing the system volume. Below a certain dilation rate, the system is still able to jam for ϕ smaller than the initial ϕ. We measure γ for different dilation rates and initial packing fractions by monitoring the coordination number of non-rattlers and the system pressure. We find that γ is the same as the γ required to jam a system with fixed packing fraction ϕ via pure shear. Graphic abstract: [Figure not available: see fulltext.].

Duke Scholars

Author Joshua Socolar Physics