Modeling damage and plasticity in aggregates with the material point method (MPM)

In order to simulate the failure of aggregate materials, a coupled damage and plasticity model is used with the material point method (MPM). A pressure-dependent J2 plasticity law, the Drucker-Prager model, is combined with the Grady-Kipp damage evolution model. This allows the simulation of both simple brittle failure and more complex, multi-mode failure cases. The meshfree method, MPM, employs Lagrangian particles to follow the geometry and stores the state of the material on those particles. The large deformations and complex physics associated with fracturing can be handled in a straightforward manner using MPM. This work first describes the two models used to quantify failure in the context of the MPM algorithm. Validation of the model is carried out by studying the stress and failure response of the well-studied Brazilian Test. The framework is then compared against real experimental data of uniaxial compression of gypsum samples with an embedded flaw. Finally, as an additional use case, protection strategies for Roman Columns in Pompeii are evaluated.