Implementation of an Object Oriented Library of Constitutive Models for DEM in the KRATOS Framework

As a program increases its size and complexity, it can rapidly turn into something pretty difficult to keep controlled and up-to-date, specially when the developing work is shared between an extensive group of people. Keeping this in mind, it is pretty straightforward to understand why over the last few years, the emphasis in the design of programs has shifted from the design of procedures and toward an efficient organization of data. Modern DEM codes usually take advantage of parallel processing capabilities (shared or distributed systems) to scale up the number of particles or length of the simulation and this would be more difficult to achieve without good foundations in the code structure. In this context, the main objective of this work will be the implementation of an efficient constitutive model library for discrete element based simulations. A well-defined and flexible structure in which modifying or introducing new constitutive equations will be easier, keeping the main program strategy mostly unchanged while minimizing, at the same time, the risk of error during the execution of the program. Furthermore, the existing basic user interface currently used for introducing the data in the pre-process stage will need to be updated in order to use the newly introduced developments in the DEM code. Finally, several numerical examples will be runusing the available constitutive equations from the library, comparing the obtained simulation results with published experiment data.