Granular materials, either in nature or industry, present a lot of different shapes and a wide range of sizes. These variations in size and shape are some examples of what is called grain polydispersity.
In physical experiments, it is quite difficult to control grain size span and it is even more challenging to control or quantify particle shape variability. In a real granular material, we may find boulders, limes, clays… but standard testing machines are not able to contain representative samples containing all these soil types.
But… there is numerical simulation! In recent years, discrete element simulations have permitted to grasp more and more characteristics of behavior of polydisperse packings. The most of then by means of 2D simulations though.
3D simulations are challenging. They require a large number of particles, an adequate sample construction and treatment of interactions between the particles, and small time steps. Thus… they are very long simulations.
By means of the contact dynamics method, we were able to analyse the shear strength of different polydisperse packings with varying grain size span. Check out this exemple for one of our simulations:
Do you want to see more?
Check our paper here!