On the response of dynamic cracks to increasing overload
- Max-Planck-Institut fuer Metallforschung, Stuttgart (Germany)
One of the most interesting questions in the dynamics of brittle fracture is how a running brittle crack responds to an overload, i.e., to a mechanical energy release rate larger than that due to the increase in surface energy of the two cleavage surfaces. To address this question, dynamically running cracks in different crystal lattices are modelled atomistically under the condition of constant energy release rate. Stable crack propagation as well as the onset of crack tip instabilities are studied. It will be shown that small overloads lead to stable crack propagation with steady state velocities which quickly reach the terminal velocity of about 0.4 of the Rayleigh wave speed upon increasing the overload. Further increasing the overload does not change the steady state velocity but significantly changes the energy dissipation process towards shock wave emission at the breaking of every single atomic bond. Eventually the perfectly brittle crack becomes unstable, which then leads to dislocation generation and to the production of cleavage steps. The onset of the instability as well as the terminal velocity are related to the non-linearity of the interatomic interaction.
- OSTI ID:
- 400635
- Report Number(s):
- CONF-951155-; ISBN 1-55899-312-6; TRN: IM9650%%40
- Resource Relation:
- Conference: Fall meeting of the Materials Research Society (MRS), Boston, MA (United States), 27 Nov - 1 Dec 1995; Other Information: PBD: 1996; Related Information: Is Part Of Fracture -- Instability dynamics, scaling, and ductile/brittle behavior; Selinger, R.L.B.; Fuller, E.R. Jr. [eds.] [National Inst. of Standards and Technology, Gaithersburg, MD (United States)]; Mecholsky, J.J. [ed.] [Univ. of Florida, Gainesville, FL (United States)]; Carlsson, A.E. [ed.] [Washington Univ., Saint Louis, MO (United States)]; PB: 420 p.; Materials Research Society symposium proceedings, Volume 409
- Country of Publication:
- United States
- Language:
- English
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