题目：A semi-automated high-order modelling and simulation approach for in-vivo bone analyses
报告人：Martin Ruess (英国格拉斯哥大学)
In this talk a high-order analysis framework for bone mechanics simulation is presented. The method employs unfitted finite element meshes and voxel quadrature rules to seamlessly transfer CT data into a patient-specific bone discretization. It further applies a phase-field based formulation for imposing traction constraints in a diffuse sense ［1］. The essential component of this approach is a diffuse geometry model generated from a metastable phase-field solution of the Allen-Cahn problem that assumes the imaging data asinitial condition. It will be shown that in the context of the voxel finite cell method［2］, diffuse boundary conditions achieve the same accuracy as boundary conditions defined over explicit sharp surfaces, if the inherent length scales, i.e., the interface width of the phase-field,the voxel spacing and the mesh size, are properly related. The flexibility of the proposed method and its suitability for the clinical use will be demonstrated by analysing stresses in a human femur and a vertebral body.
［1］L.H. Nguyen, S.K.F. Stoter, T. Baum, J.S. Kirschke, M. Ruess, Z. Yosibash, D. Schillinger (2017). Phase-field boundary conditions for the voxel finite cell method: surface-free stress analysis of CT-based bone structures, Int'l Journal for Numerical Methods in Biomedical Engineering, DIO: 10.1002/cnm.2880
［2］D. Schillinger, M. Ruess(2015). The Finite Cell Method: A review in the context of higher-order structural analysis of CAD and image-based geometric models, Archives of Computational Methods in Engineering 22(3), pp. 391-455.
Dr. Martin Ruess is Associate Professor at the School of Engineering, University of Glasgow, UK. Dr. Ruess graduated from TU Berlin with a diploma and a PhD-degree in Civil Engineering and received a Habilitation-degree from TU München. Prior to his appointment at Glasgow, Dr. Ruess worked as Assistant Professor at TU Delft, as Visiting Professor at TU Berlin and Research Associate at TU München. Dr. Ruess' scientific background is computational mechanics with a focus on higher-order approximation methods, immersed boundary methods and bio-mechanical simulations. In his recent work Dr. Ruess has focused on weak enforcement methods for boundary and coupling conditions in isogeometric analysis and fictitious domain methods, reduced-order models for stability analyses of thin-shell structures and validated bone mechanics simulations.