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Sahir Butt, Günther Meschke

• In this study, we investigate the dynamic fracture process in amorphous brittle materials using 3D peridynamic analyses of dynamic crack propagation in PMMA plates subjected to quasi‐static loads. This loading condition allows one to assume, that the crack will accelerate to a steady‐state velocity and will continue propagating straight forward at a constant velocity. Dynamic crack instability and its effect on the fracture surface creation as well as the dissipated energy is analyzed numerically for cracks propagating at different velocities. Simulations reproduce many salient features of experimental observations, such as instabilities occurring at the crack tip for cracks propagating above a certain critical velocity. It is shown from the simulations, that increasing crack velocity results in excessively repeated micro‐branching. An increased energy dissipation is also observed at higher crack velocities in the simulations, which correspond to the well known velocity toughening effect. Simulations also reproduce a limiting crack speed, which is below the theoretical limit, i.e. the Rayleigh wave speed.