PARTICLE MODEL FOR QUASIBRITTLE FRACTURE AND APPLICATION TO SEA-ICE

Fracture of quasibrittle materials with a large zone of distributed cr acking is simulated by the particle model (discrete element method). T he particles at the microlevel interact only by central forces with a prescribed force-displacement or stress-strain relation, which exhibit s postpeak softening and is characterized by microstrength and microfr acture energy. It is shown that a regular lattice, even though capable of closely approximating isotropic elastic properties, exhibits stron g directional bias favoring propagation along a few preferred directio ns. A randomly generated particle model has no such bias. With a prope r choice of the microlevel constitutive law, it can realistically simu late fracture of an ice flee during impact on a rigid obstacle. Explic it integration of the equations of motion is used to simulate the impa ct process and to explore the effect of the flee size and its initial velocity on the failure pattern and the history of the contact force.