An algorithm to simulate surface creation without element deletion or remeshing

One of the major obstacles to modelling discrete fracture and fragmentation of materials within the nite element (FE) framework is the inability to easily model the resulting geometry changes. This paper presents an algorithm for three-dimensional element cohesion and separation implemented in the explicit FE code DYNA3D. The algorithm handles mesh de nition and solution di culties necessary for general element separation with minimal additional e ort required of the user. The algorithm modi es the standard mesh de nition so that element separation does not require remeshing. The original continuity of the structure is maintained by averaging the nodal accelerations for each coincident node set then applying this average acceleration to each of the nodes in the set. When speci ed failure criteria for an interface are met, averaging is no longer performed, thereby allowing the coincident nodes to separate and create new surface. The new surface can be automatically incorporated in the contact de nition so that the contact of these new surfaces is modelled using the same contact considerations of the original FE model. Following a discussion of historical and current FE fracture=fragmentation models, the general framework of the algorithm is presented. Also, results are presented which show that the algorithm simulates surface creation in a variety of simulations