"Force and Failure in Bonded Granular Packings"
What interests me about this project is that not much previous work had been done in it, considering we had a new faculty member join the physics department this year. That means that all the work and different steps I took in completing my project were my own thought-out ideas. The amount of freedom and flexibility in my project made it all the more better.
Using a casting technique, we fabricate photoelastic grains that exhibit stress-induced birefringence. We visualize force transmission in granular packings via the spatial modulation of the birefringence. We also fabricate bonded packings, using various adhesives, and subject them to uniaxial compression tests. Using a digital camera, a polariscope, we perform photoelastic measurements of stress propagation and failure in 2D granular packings under uniaxial compression. We use two techniques to bond our grains: we harden capillary bridges of Loctite cyanoacrylate glue and embedded particles in a matrix made from water, flour, and corn syrup. Bonded packings prepared in these fashions exhibit failure via grain deformation and bond breakage, respectively.
Photoelastic images of the paste bonded packing under compression at 1 mm compresson. Force chains are already seen in most of the grains, exhibiting low spatial heterogeneity.