Three dimensional fragmentation simulation of concrete structures with a nodally regularized meshfree method

A three dimensional large deformation meshfree simulation of concrete fragmentation is presented by using a nodally regularized Galerkin meshfree method. This nodally regularized meshfree method is established with the two-level Lagrangian nodal gradient smoothing technique to relieve the material instability in failure modeling. The rate formulation is employed for the treatment of large deformation and therefore the two-level gradient smoothing is performed for the rate of deformation tensor and the deformation gradient. The essential characteristic of the present approach is that all the variables are conveniently computed at the meshfree nodes, which allows an efficient evaluation of the Galerkin weak form. The concrete failure is described by the KCC concrete model with three independent strength surfaces. This model has a pressure dependent evolving failure surface that is built with an internal damage variable. The computational implementation of the given concrete model within the context of meshfree formulation is discussed in detail. The effectiveness of the present method is demonstrated through several numerical examples of concrete structures.