Mechanics of a model cohesive granular medium


Lucas Goehring
Mechanics of a model cohesive granular medium

10. April 2019, 17.00
WW8, Raum 2.018, Dr.-Mack-Str. 77, Fürth

I will present and discuss the mechanics of a model material, composed of glass beads held together by solidified polymer bonds, or bridges.  The failure of such cohesive granular media are relevant to a broad range basic and applied questions, including the hydraulic fracture of rock, bio-deterioration of sculpture and stonework, root growth in soils, the strength of agglomerates, and powder aggregation.   In this talk I will show how to prepare a simple model material, with tunable elastic and fracture properties, by mixing a curable polymer into a granular medium to form a network of capillary bridges, and then curing that polymer in place.  The mechanical response of the resulting material can be controlled by over three orders of magnitude, by adjusting the size and stiffness of the bridges, and the size of the particles.  I will also describe its mechanism of failure, by both uniaxial compression (in combination with in-situ x-ray microtomography), and notch tests.  Finally, I conclude by showing how the material has a potential for use as a reliable model material, with robust and controllable properties, in the study of the fracture and failure of composite systems.