Image analysis of the kinematics and size reduction of grains in cataclasis
Granular systems that undergo comminution (i.e., grain size reduction) under working loads are ubiquitous in naturally occurring problems. For example, granular particles in shearing fault gouges undergo cataclasis. Grain crushing in shearing systems is also important in many manmade engineering systems. Larger particles have statistically more cracks within them which decreases their crushing resistance, making them susceptible to crushing from the point of view of strength. Smaller particles contact less surrounding particles, therefore undergo more internal shear, making them susceptible to crushing from the point of view of the boundary conditions. In combination, the strength and coordination number effects are in competition, explaining why at the end of the comminution phase, both bigger and smaller particles could be found; an ultimate grading is normally fractal. The experimental challenges in this research will be quite unique in that we will endeavor to see and thereafter analyse the kinematics and the grain size reduction using two novel in-vivo testing techniques.