Modelling Compressive Failure Using Rigid Particle Systems

A rigid particle model is used to simulate mesoscopic failure pro- cesses in cement-based composites. Concrete continua are dis- cretized using a large number of Voronoi polygons, each polygon being a rigid element. Concrete is represented using a three com- ponent model: cement matrix, aggregate inclusions, and matrix- inclusion interfacial zones. Special attention is given to creating the aggregate inclusions as part of the polygonal mesh. These rigid elements are interconnected by a spring system distributed over the polygon boundaries; spring properties are set according to component type which they represent. In order to better represent the three-dimensional nature of the material and fracture process, springs properties degrade gradually, based on a measure of damage related to component type. Numerical results are given for differ- ent types of loadings, including a uniaxial compression test and a split-cylinder tension test. 375 1 The modes of concrete specimens subjected to compression are dependent on the material constituents, specimen geometry dimensions, the boundary conditions the load application points. is therefore to form consistent interpretations of concrete failure for design purposes. Two main modes of ure are witnessed during testing, those being tensile-type splitting directed along compression axis and compressive-type diagonal shear However, are still numerous questions regarding the mechanisms underlying failure, including those concerning the conditions for failure initiation. for analyzing concrete materials, including most element approaches, enforce geometric compatibility amongst the model components. Due to these compatibility con- straints, such models have difficulty in simulating failure modes following the post-peak response.