Andersen, Søren

English

Formålet med denne afhandling er at anvende og forbedre materialepunktsmetoden for modellering af geotekniske problemer. Et geoteknisk fænomen, der er genstand for aktiv forskning, er studiet af jordskred. En stor del af den eksisterende forskning er forkuseret på forudsigelse af, hvornår skråninger bliver instabile. Ved hjælp af kommerciel finite element eller finite difference software som Plaxis, ABAQUS eller FLAC er det muligt at forudsige stabiliteten af visse typer af skråninger. Dynamikken under et jordskred er imidlertid mindre udforsket.Materialepunktsmetoden (MPM) er en nyskabende numerisk metode specielt designet til at analysere problemer, der involverer materialer udsat for store tøjninger i et dynamisk tid–rum domæne. Afhandlingen udforsker materialepunktsmetoden med specielt fokus på at forbedre modelleringen af problemer, der involverer store flytninger. Geotekniske problemer med store tøjninger så som jordskred er en stor udfordring at modellere nummerisk. Ved at kombinere materialepunkter, der indeholder de relevante tilstandsvariabler, og et beregningsnet, hvor bevægelsesligningen løses, er materialepunktsmetoden i stand til at undgå nogle af problematikkerne, der er forbundet med de traditionelle metoder såsom finite element metoden. Imidlertid er der nye væsentlige udfordringer, der behandles i denne afhandling.Afhandlingen diskuterer de nyeste ideer indenformaterialepunktsmetoden. Endvidere præsenteres ideer til at repræsentere problemer med ekstreme deformationer. Den numerske model, der ligger til grund for resultaterne i denne afhandling er baseret på den generaliserede interpolationsmaterialepunktsmetode (GIMP). En del af forskningsresultaterne i denne afhandling er præsenteret i form af tre forskningsartikler.The aim of this thesis is to apply and improve the material-point method for modelling of geotechnical problems. One of the geotechnical phenomena that is a subject of active research is the study of landslides. A large amount of research is focused on determining when slopes become unstable. Hence, it is possible to predict if a certain slope is stable using commercial finite element or finite difference software such as PLAXIS, ABAQUS or FLAC. However, the dynamics during a landslide are less explored.The material-point method (MPM) is a novel numerical method aimed at analysing problems involving materials subjected to large strains in a dynamical time–space domain. This thesis explores the material-point method with the specific aim of improving the performance for geotechnical problems. Large-strain geotechnical problems such as landslides pose a major challenge to model numerically. Employing material points to track all relevant variables and a computational grid to solve the equations of motion, the material-point method avoids some of the problematic issues associated with traditional numerical models such as the finite element method. However, several challenges for the method exist as discussed in this thesis.The thesis discusses the state of the art of the material-point method. Further, it presents ideas to better represent problems involving extreme deformations utilizing the framework of the generalized interpolation material point method (GIMP). Some of the results of this thesis are presented in the form of three research papers

Material-Point Analysis of Large-Strain Problems:modelling of landslides

https://vbn.aau.dk/ws/files/56400659/Material_Point_Analysis_of_Large_Strain_Problems.pdf

Material-Point Analysis of Large-Strain Problems:modelling of landslides

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