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Session G03 - Computational Materials II.
session, Tuesday afternoon, June 7, 14:00
Allegheny Room, Westin William Penn Hotel
A simple dynamic network model is constructed to simulate fracture and viscoelastic behaviour in two dimensional mechanical systems under constantly increasing elongation. In the model disorder is introduced as quenched. The force field is estimated from the Born Hamiltonian, which accounts for the elastic interactions between lattice sites. In order to mimic the local adjustment of the material to the stress, relaxation effects are included via Maxwellian viscoelasticity. This is reflected both in the macroscopic response of the system and the fracture behaviour. We analyze the interplay between disorder and dissipation in dynamic fracture, and study the characteristics of crack formation and propagation, when the time scales of dissipation and loading are varied relative to each other. In weakly disordered systems, different regimes can be distinguished in the fracture process. Brittle-type behaviour, as observed in quasistatic fracture models, is encountered in the adiabatic limit of slow straining. At larger strain rates and with increasing dissipation, the development of damage shows more ductile-like characteristics, which inhibits the crack growth. The behaviour of the system has also been demonstrated with animations, which illuminate the propagation of dynamic disturbances from the crack tip.