Numerical simulations of fracture initiation in ductile solids under mode I, dynamic loading |
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Authors: | R Narasimhan S Basu |
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Affiliation: | (1) Department of Mechanical Engineering, Indian Institute of Science, 560 012 Bangalore, India |
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Abstract: | In this paper, an overview of some recent computational studies by the authors on ductile crack initiation under mode I, dynamic
loading is presented. In these studies, a large deformation finite element procedure is employed along with the viscoplastic
version of the Gurson constitutive model that accounts for the micro-mechanical processes of void nucleation, growth and coalescence.
A three-point bend fracture specimen subjected to impact, and a single edge notched specimen loaded by a tensile stress pulse
are analysed. Several loading rates are simulated by varying the impact speed or the rise time and magnitude of the stress
pulse. A simple model involving a semi-circular notch with a pre-nucleated circular hole situated ahead of it is considered.
The growth of the hole and its interaction with the notch tip, which leads to plastic strain and porosity localization in
the ligament connecting them, is simulated. The role of strain-rate dependence on ductile crack initiation at high loading
rates, and the specimen geometry effect on the variation of dynamic fracture toughness with loading rate are investigated. |
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Keywords: | Ductile fracture dynamic loading strain-rate dependence finite elements |
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