A new mixed-mode fracture criterion for large scale lattice models.

Reasonable fracture criteria are crucial for the modeling of dynamic failure in computational spring lattice models. For experiments on the micro and on the meso scale exist successful criteria, which are based on the stress that a spring experiences. In this paper we test the applicability of these failure criteria to large scale models, where gravity plays an important role in addition to the externally applied deformation. The resulting brittle structures do not resemble the outcome predicted by fracture mechanics and geological observations. For this reason we derive an elliptical fracture criterion, which is based on the strain energy stored in a spring. Simulations using the new criterion result in realistic structures. It is another great advantage of this fracture model, that it can be combined with classic geological material parameters: the tensile strength σ₀ and the shear cohesionτ₀. While we tested the fracture model only for large scale structures, there is strong reason to believe that the model is equally applicable to lattice simulations on the micro and the meso scale. [ABSTRACT FROM AUTHOR]