An appropriate description for modeling the post-failure behavior of material is often crucial when modeling impact problems involving large deformations and material failure. In [1], a coupling method for integrating a meshfree particle method in a mesh-based hydrocode has been developed. The procedure allows for an adaptive coupling in the sense that, at the beginning of a computation, an entire structure is discretized homogeneously using standard Finite Elements. As large deformations occur, the discretization is modified in the affected areas, i. e., elements are converted into particles. The particle description is based on a meshfree particle method for continua, in fact a further development of the well-known Method of Smoothed Particle Hydrodynamics (SPH) is employed. This procedure proves very useful for modeling large plastic flows in impact problems. However, if fragmentation occurs, a continuum description has a number of restrictions, requires very fine resolutions, and gets computationally expensive in 3D. Therefore another discretization transition is used: a transition from particles representing continua to particles representing discontinuous media ("discrete particles"). The latter have similarities to the so-called Discrete Element Method. The paper describes the basic features and differences between the continuous and discontinuous meshfree particle methods. Further on, it shows how the transition between discretizations is implemented in the Institutes in-house code SOPHIA. Advantages and problems of the new method are being addressed. Application of the method to dynamic material failure is shown for typical material tests used in order to experimentally characterize material behavior under impact conditions.
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