02 Fakultät Bau- und Umweltingenieurwissenschaften

Permanent URI for this collectionhttps://elib.uni-stuttgart.de/handle/11682/3

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Publication Type: search.filters.UBSTyp.DissertationSubject: search.filters.subject.610

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    A modelling-simulation-analysis workflow for investigating socket-stump interaction
    (Stuttgart : Institute for Modelling and Simulation of Biomechanical Systems, Chair of Continuum Biomechanics and Mechanobiology, University of Stuttgart, 2019) Ramasamy, Ellankavi; Röhrle, Oliver (Prof., PhD)
    In this thesis, a novel subject-specific modelling-simulation-analysis workflow is developed, which generates detailed stump models for analysis in a continuum-mechanical framework. With minimal human intervention, detailed stump models are generated from medical images, and are used in Finite Element (FE) simulations to study dynamic stump-socket interactions. Herein, the stump is composed of bone, individual muscles and fat, as opposed to the state-of-the-art models with fused muscles. An additional model representing the state-of-the-art stump geometry is generated for comparison with the proposed model. To showcase the necessity of detailed stump models, the state-of-the-art model is compared with the detailed model in a bipedal stance simulation. For this purpose, a nonlinear hyperelastic, transversely isotropic skeletal muscle constitutive law containing a deep tissue injury model, using continuum damage mechanics, is implemented in LS-DYNA. Internal strains and deep tissue injury during dynamic socket-stump interaction are analysed with bipedal stance and gait simulations. Further, the potential of forward dynamics with active stump models, and the possibility of realistic liner donning simulations are presented. Finally, the possibilities of using the proposed workflow in the context of determining socket fit and comfort are discussed.
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    Image-based analysis of biological network structures using machine learning and continuum mechanics
    (Stuttgart : Institute for Modelling and Simulation of Biomechanical Systems, Chair of Continuum Biomechanics and Mechanobiology, University of Stuttgart, 2020) Asgharzadeh, Pouyan; Röhrle, Oliver (Prof., PhD)
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    Simulating vertebroplasty using a multiphase continuum-mechanical approach : rheological characterization, numerical simulations, and experimental validation
    (Stuttgart : Institute for Modelling and Simulation of Biomechanical Systems, Chair of Continuum Biomechanics and Mechanobiology, University of Stuttgart, 2024) Trivedi, Zubin; Röhrle, Oliver (Prof., PhD)
    Percutaneous vertebroplasty is a surgical procedure for treating vertebral fractures involving injection of a so-called "bone cement'' into the vertebra. This Ph.D. thesis aimed to develop a computational model for simulating vertebroplasty, and thereby help practitioners determine the best operating parameters specific to each patient. The computational model employs a multiphase continuum-mechanical approach based on the Theory of Porous Media, along with discretization and upscaling methods specifically chosen and modified to suit the application. Apart from this, experiments were carried out to understand the behaviour of the bone cement in the context of vertebroplasty so that its behaviour can be correctly modelled. The developed computational model is validated using experiments done using a simple benchmark experiment. The simulations shed light on some crucial mechanical aspects of vertebroplasty that could determine the success or failure of the procedure.