Contact description in numerical simulation for rock mechanics

Rock and Rock mass are typical discontinuous materials. A proper contact mechanism is the prerequisite to perform discontinuous numerical simulations. At present, analytical models, physical models and parameterized models are broad used. Physical models are suitable for explicit methods while parameterized models are suitable for implicit methods. The penalty model has the advantage of not increasing the unknown variables but the choice of the penalty number is difficult. In this paper, a spherical contact model is presented using penalty method and open-close iteration algorithm. The model is validated by the collision test which describes the contact properties of materials. The results show that penalty numbers can be filtered with given maximum interpenetration rate and the coefficient of restitution.