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2014

Schneider, Markus, Spray, John, Rogers, Robert, Hogan, James, Vincent, Gregory

The dynamic fragmentation of a fine grained granitoid material has been examined. Target thicknesses ranged from 7 to 40 mm and impact energies from 12 to 2,500 J. Combined particle image velocimetry and image enhancement techniques are introduced and have been used to measure the size and...

2012

Boonsue, Suporn, Rogers, Robert, Spray, John, Hogan, James

The role of plastic deformation and fracture during small-scale, low-rate contact scenarios in gypsum is investigated. Results indicate that the hardness decreases with increasing load, on all axes, ranging from 216 kg/mm2 at 0.25 N to 91 kg/mm2 at 4.91 N on the (010) plane and from 122 kg/mm2 at...

2011

Vincent, Gregory, Boonsue, Suporn, Rogers, Robert, Spray, John, Schneider, Markus, Hogan, James

The dynamic fracture of natural polyphase ceramic (granite) blocks by high-speed impact at 207 m/s, 420 m/s and 537 m/s has been investigated. An electromagnetic railgun was used as the launch system. Results reveal that the number of fragments increases substantially, and the dominant length...

2015

Ramesh, K.T., Farbaniec, Lukasz, Hogan, James

Brittle failure in boron carbide has been studied in dynamic uniaxial compression using a Kolsky bar technique. A detailed study of fragments was performed using SEM-EDS, to identify the mechanisms responsible for failure. Microstructural characterization and fracture surface observations...

2016

Farbaniec, Lukasz, Daphalapurkar, Nitin, Ramesh, K.T., Hogan, James

Dynamic brittle fragmentation is typically described using analytical and computational approaches for tensile stress-states. However, most fragmentation applications (e.g., impact, blast) involve very large initial compressive stresses and deformations. In this study, the compressive...

2014

Farbaniec, Lukasz, Shaeffer, Matt, Ramesh, K.T., Hogan, James

We investigate the rate-dependent compressive failure and fragmentation of a hot-pressed boron carbide, under both uniaxial and confined biaxial compression, using quantitative fragment analysis coupled with quantitative microstructural analysis. Two distinct fragmentation regimes are observed,...