Experimental and numerical investigation of Weibullian behavior of grain
crushing strength
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Abstract
The Weibullian behavior of single grain crushing strength was investigated experimentally and numerically with
the aim of enhancing the understanding of rock grain breakage. The morphologies of pebble grains were obtained
using white light 3D laser scanning and image processing. A grain shape library was constructed for grain shape
analysis with different shape descriptors. The use of the shape library and grain stability analysis is discussed for a
suggested procedure to rotate a grain to its most stable configuration. Single grain crushing tests were performed
for 30 pebbles to obtain force-displacement curves and fracture patterns. Each grain was compressed diametrically
between flat platens. As expected, the values of the stress at bulk fracture follow a Weibull distribution. A
procedure for generating crushable agglomerates with realistic particle shapes was demonstrated, which was
accomplished in the discrete element modeling (DEM) of the single grain crushing test. The work presented here
is novel in that both the heterogeneous micro-structures and randomly distributed flaws are considered. The DEM
results demonstrate that the proposed modeling approach and calibrated parameters are reliable and can reflect
the crushing behavior of rock pebbles. Finally, three parametric studies were presented evaluating the effects of
micro-crack density, micro-crack disorder, and grain morphology on the Weibullian behavior of the crushing
strength, none of which has previously been thoroughly considered. These three studies provide a deeper insight
into the origin of the Weibullian behavior of single grain crushing strength.
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