Dokument-ID Dokumenttyp Autoren/innen Persönliche Herausgeber/innen Haupttitel Abstract Auflage Verlagsort Verlag Herausgeber (Institution) Erscheinungsjahr Titel des übergeordneten Werkes Jahrgang/Band ISBN Veranstaltung Veranstaltungsort Beginndatum der Veranstaltung Enddatum der Veranstaltung Ausgabe/Heft Erste Seite Letzte Seite URN DOI Lizenz Datum der Freischaltung OPUS4-48588 Vortrag Cuéllar, Pablo A GPU-based micromechanical simulation model for submerged geotechnical problems Driven steel piles are commonly used as deep foundations for a wide range of engineering structures, particularly in the offshore branch. They are also an interesting example among the broad spectrum of geotechnical applications where the fluid-solid interaction at the pore-scale can play a major role for the macromechanical behaviour of the whole system. In the context of the geotechnical practice for offshore wind-farm structures, both the industrial design and the actual dimensions of the large piles used as foundations in the seabed are often driven by factors such as the soil resistance to driving (SRD), which are still not well understood and often estimated based on mere empirical correlations or overly simplified one-dimensional models. In particular, the role of the micromechanical effects during the installation process (e.g. local dilatancy or contractancy) and their consequences on the pore pressure levels at the pile-tip and on the effective resistance to driving, are generally either disregarded or at most assumed to be covered by the simplified engineering "black-box" solutions. Here, we propose a general framework to address such local aspects of a geotechnical application involving fluid-saturated soils while retaining the focus on the micro-scale phenomena. We advocate for an approach that combines the relative simplicity of the Discrete Element Method (DEM) for the solid mechanics with the capabilities of the Lattice Boltzmann Method (LBM) for the fluid dynamics. In this sense, we aim to compile some useful techniques and practical recommendations for an efficient GPU-based implementation of a micromechanical LBM-DEM simulation tool. 2019 DEM8, the 8th International Conference on Discrete Element Methods University Twente, Enschede, The Netherlands 20.07.2019 26.07.2019 2019-08-01 OPUS4-51866 Vortrag Cuéllar, Pablo An efficient GPU implementation of a micromechanical computational tool for erosion problems We present here a set of conceptual and numerical tools for a micromechanical simulation of general erosion problems involving fluid-saturated granular assemblies, whether frictional or cohesive. We propose a parallel computation using graphical processing units (GPUs) to treat large numbers of degrees of freedom with conventional desktop computers. The fluid phase is here simulated with a particle-resolved approach in the frame of the Lattice Boltzmann Method (LBM) while the granular solid phase is modelled as a collection of discrete particles from a Molecular Dynamics DEM perspective. The range of possible material behaviors for the solid granular phase is intended here to cover a broad spectrum from purely frictional to viscous cohesive materials with either brittle or transient debonding features. Specific details of the implementation and some validation cases will be put forward. To conclude we provide some exemplary applications in the field of soil erosion along with details on the parallel performance of the models. The results show that a micromechanical approach can be feasible and useful in practice, providing meaningful insights into complex phenomena like the erosion threshold and kinetics of weakly cemented soils. 2020 EWG-IE 2020 Workshop on "Innovative numerical methods for internal erosion processes" Online meeting 17.12.2020 2020-12-28 OPUS4-42459 Vortrag Cuéllar, Pablo Erosive phenomena at the mesoscale - Perspectives and challenges using coupled LBM-DEM models The physical phenomena related to the erosion of granular materials by a fluid flow are ubiquitous and often present major challenges and threats to a wide range of civil engineering constructions and infrastructures. Catastrophic earth-dam failures and large sinkholes are just some of the possible outcomes of the different forms of erosion (a.o. surface erosion, suffusion, piping, backwards erosion, etc…). However, little is known about the actual mechanical origins of erosion, while the assessment of erodibility is generally performed by means of experimental tests and empirical correlations. Here we provide a general overview of some current research models aiming to clarify the micromechanical phenomena and their macromechanical consequences taking place in different erosion scenarios. The employed numerical techniques rely on the coupling of two well-stablished particle methods for the fluid and solid phases, namely the Lattice Boltzmann Method (LBM) and the Discrete Element Method (DEM) respectively. Further ingredients of our numerical models include an elastoplastic cohesion model for intergranular solid bridges and a subcritical debonding model for the simulation of transient damage processes within the soil matrix. 2017 5th Int. Conference on Particle-based Methods (PARTICLES 2017) Hannover, Germany 26.09.2017 28.09.2017 2017-10-11