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    Hertzian contact damage in a hollow circular cylinder
    (International Society for Rock Mechanics, 2016) Serati, M.; Williams, D.J.; Erarslan, N.
    This paper attempts to provide a theoretical framework for the determination of the stress state induced in a hollow cylinder (ring) under Hertzian compressions on its outer boundary. The solution is obtained using Airy stress functions, Michell-Fourier series expansions and Fourier-Bessel series expressions in polar coordinates. Parametric studies are also performed to investigate the influence of the loading angle and the geometrical aspect ratio of the ring on the induced stress tensor. © 2016 Taylor & Francis Group, London, ISBN 978-1-138-03265-1
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    Micro-mechanical and micro-structural aspects of strength variation in rocks under various loading conditions
    (TMMOB Maden Muhendisleri Odasi, 2015) Erarslan, N.; Ghamgoshar, M.; Williams, D.J.
    This research focuses on the micro-mechanical and micro-structural aspects of strength variation in macro-scale rock structures, because final failure of rocks comes about through a process of interaction/coalescence among the many load-parallel or load-inclined tensile fractures that are generated by micro pre-existing cracks. Provide major contributions to the understanding of stress-induced micro-fracturing of rock under various loading conditions, static and dynamic, resulting in the degradation of macro-scale rock strength, or possibly strain-hardening, of rocks. The outcome of this research is expected to provide rock cutting, civil-geotechnical and mining design engineers with access to new, more accurate rock strength estimation methods, of high value for minimising the risks associated with rock strength uncertainty. A brittle rock type Brisbane tuff specimens were tested. Through the combined use of laboratory tests, Scanning Electron Microscope (SEM) techniques, and Computed Tomography (CT) scan technique, the damage mechanism of rocks under various loading conditions, including static and cyclic, were examined in nano-scale and the results were compared with each other for the first time in literature. Moreover, the sub-critical crack propagation phenomena , which is used to explain the premature failure of ceramics and metals and Fracture Process Zone (FPZ) phenomena, are explained in this research in terms of micro-mechanical strength reduction due to rock fatigue. Thus, modelling and understanding the crack propagation behaviour depending on different amplitude and frequencies are believed very important for the dynamic rock cutting researches and rock cutting machine manufacturers.