Modeling of concrete failure under blast and fragment loading

The defense community is extremely interested in developing numerical methodologies for predicting the dynamic response of concrete materials under extreme loading conditions. This capability would make it possible to use computer software for simulating events of interest, such as the response of concrete structures or structural components to blast and fragment impact. Over the years, substantial effort has been invested in researching analytical models and methods to develop this capability. Most of this effort has focused on in improving methodologies that are based on continuum mechanics. However, (classical) continuum mechanics is not well suited for the simulation of concrete in the post-failure regime. This is mainly due to the non-homogenous nature of concrete as well as the discontinuous nature of fracture and fragmentation. To overcome these limitations, ES3 and Prof. Cusatis at RPI have jointly formulated and implemented a new innovative methodology: the Lattice Discrete Particle Model (LDPM). LDPM is a methodology that treats concrete at the meso-scale, the scale of the largest aggregate pieces. LDPM models the heterogeneities in concrete and is capable of simulating discrete cracking leading to fragmentation in a physically realistic fashion. In Phase I, we have demonstrated how LDPM can be integrated in a multi-scale computational environment. Furthermore, we have shown the feasibility of treating accurately concrete-fiber and concrete-rebar interactions. In Phase II, we are planning to Extend the Bridging-Scale Methods (BSM) to a three-dimensional framework where the fine scale solution is provided by LDPM. Validate the concrete-fiber interaction algorithm for CORTUF. Perform tests in support of the validation effort for the concrete-fiber interaction algorithm. Perform simulations of CORTUF panel penetrations. Create a library of examples and supporting documentation.