Numerical simulations of multiaxial damage behaviour of concrete using the method of discrete elements
Final Report Abstract
The Discrete Element Method (DEM) is a new, old method based on Newton's axioms, which has become practicable thanks to the rapid development of computing technology over the past fifty years. It is a method that is easy to describe, can be used in a variety of ways, but is computationally intensive. The method makes it possible to achieve spectacular results with comparatively little programming effort. The need to solve weakly populated large linear systems of equations is eliminated, as are complicated mesh generation, the assembly of system matrices and the associated complex optimization strategies. The method of discrete elements implicitly obeys strictly those – always valid – energy principles to which other methods such as the finite element method explicitly refer in their derivations, while they actually only work with approximations for (very) small deformations. With an appropriate interpretation, all elements involved in the simulation can be understood as material components or based on the interaction of material components. Contact elements or even suitably placed crack elements are not required. Cracks are manifested by the absence of material. The phenomenon of overadditivity is inherent in particle simulations from the outset. Particle methods are therefore ideally suited to the model-based study of complex systems. Parameter identification and parameter adjustment of discrete element models are difficult as soon as the validity of the superposition principle is no longer given. However, this is not a shortcoming of the method, but a consequence of interaction and over-additivity. The method is ideal for generating virtual test specimens and for pre-processing in conjunction with other simulation methods. Visualizations of the results obtained with particle methods are of high illustrative and didactic value. The method is very flexible, so that the simulation results do not need to be artificially exaggerated if the parameters are set appropriately. The discrete element method is a discovery method. Like any other method, it has the character of a method, and the models developed on its basis – like all models – have the character of a model.
Publications
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Viel-Teilchen-Simulationen zum mehraxialen Schädigungsverhalten von Beton. Beiträge zur 1. DAfStb-Jahrestagung mit 54. Forschungskolloquium in Bochum, 07.-08.11.2013, Ruhr-Universität Bochum, 2013, S. 365–370
Reischl, D. S.
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Virtual Concrete Specimens: Discrete Element Simulations of the Quasistatic and Dynamic Material Behavior and Failure Mechanisms of Concrete and Mortar. IV International Conference on Particle-based Methods – Fundamentals and Applications (PARTICLES 2015), 28.–30.09.2015, Barcelona, Spanien, S. 367–378
Reischl, D. S. & Curbach, M.
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Virtual Concrete Specimens – A Discrete Element Approach to the Generation of Densely Packed Ensembles of Virtual Aggregates. In: Prof. of 5th International Conference on Particle-based Methods, Fundamentals and Applications (PARTICLES 2017), 26.-28.9.2017 in Hannover, 2017
Reischl, D. S. & Curbach, M.
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A comparative study of machine learning approaches for modeling concrete failure surfaces. Advances in Engineering Software, 116, 67-79.
Reuter, Uwe; Sultan, Ahmad & Reischl, Dirk S.
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Diskrete-Elemente-Simulationen zum mehraxialen Schädigungsverhalten von Beton, Dissertation, Technische Universität Dresden, 2021, 575 Seiten
Reischl, Dirk Sören
