Model Validation and Uncertainty Quantification in Biomechanics

Gerhard A. Holzapfel is Professor of Biomechanics and Head of the Institute of Biomechanics at Graz University of Technology (TUG), Austria, since 2007. He is also Adjunct Professor at the Norwegian University of Science and Technology (NTNU), Trondheim, Norway, and Visiting Professor at the University of Glasgow, Scotland. Until 2013 he was Professor of Biomechanics at the Royal Institute of Technology (KTH) in Stockholm, Sweden, for 9 years (7 years as an Adjunct Professor). After his PhD in Mechanical Engineering in Graz he received an Erwin-Schrödinger Scholarship for foreign countries to be a Visiting Scholar at Stanford University (1993-95). He achieved his Habilitation at TU Vienna in 1996 and received a START-Award in 1997, which is the most prestigious research award in Austria for young scientists. In the following years (1998-2004) he was the Head of a research group on "Computational Biomechanics" at TUG. Among several awards and honors in the past years he is listed in "The World's Most Influential Scientific Minds: 2014" (Thomas Reuters), he received the Erwin Schrödinger Prize 2011 from the Austrian Academy of Sciences for his lifetime achievements, and he was awarded the 2021 William Prager Medal and the 2021 Warner T. Koiter Medal. Professor Holzapfel’s research includes experimental and computational biomechanics and mechanobiology with an emphasis on soft biological tissues, the cardiovascular system including blood vessels in health and disease, aortic dissections, therapeutic interventions such as balloon angioplasty and stent implantation, second-harmonic imaging microscopy and medical image processing; nonlinear continuum mechanics, constitutive (multi-scale) modeling of solids at finite strains such as cross-linked actin networks, growth and remodeling, nonlinear finite element methods, fracture and material failure. Professor Holzapfel has authored a graduate textbook entitled "Nonlinear Solid Mechanics. A Continuum Approach for Engineering" (John Wiley & Sons), and co-edited seven books. He contributed chapters to 25+ other books, and published 250+ peer-reviewed journal articles. He is the co-founder and co-editor of the International Journal "Biomechanics and Modeling in Mechanobiology" (Springer-Verlag, Berlin, Heidelberg). Malte Rolf is a postdoctoral researcher at the Institute of Biomechanics at Graz University of Technology, in Austria. His research focuses primarily on material and computational modeling of aortic dissections, ranging from multi-scale material modeling to patient-specific fluid-structure interaction modeling. In addition to his primary research focus, M. Rolf-Pissarczyk actively participates in studies on standardized best practices for the application of in silicovalidation methods and the credibility assessment of in silico methods based on ASME verification and validation standards. Xiao Yun Xu is a Professor of Biofluid Mechanics in the Department of Chemical Engineering at Imperial College London. She joined Imperial College in 1998 as a Lecturer and became a full Professor in 2009. Professor Xu’s research expertise includes computational modelling of fluid flow and mass transfer in biological systems and its biomedical applications. Her pioneering work on the development of image-based computational models for blood flow in large arteries was reported by various media, including BBC online news and Science (“How the Blood Flows”, Science, Vol. 290, November 2000). Over the last 25 years, she has established and led her research group to the cutting edge of multiscale and multi-physics modelling of transport processes in biological systems, with applications ranging from evaluations of endovascular interventional procedures for the treatment of aortic diseases to understanding of drug transport in solid tumors and thrombolytic therapies. In these fields, she has published 200+ peer-reviewed journal articles. She currently serves as an Associate Editor of International Journal for Numerical Methods in Biomedical Engineering, a member of the board of consulting editors for Journal of Biomechanics, and a member of the editorial board of Medicine in Novel Technology and Device.

• Part I. Basics and fundamentals1. Uncertainty quantification in biomechanics: probabilistic fundamentals2. Sensitivity analysis in biomechanics: addressing model complexity and uncertaintyPart II. Sources of uncertainty and variability3. Vascular models and related uncertainties in computational medicine: Tools for capturing patient specificity and variability4. Methods for assessing uncertainties of image reconstruction procedures and their propagation in in silico analyses5. 4D-flow MRI error analysis6. Uncertainties in ultrasound elastography from a continuum mechanics perspective7. Biological sex as a missing variable in biomechanical modelsPart III. Methods for uncertainty quantification8. A primer on uncertainty quantification for cardiovascular simulations9. An introduction to multi-fidelity uncertainty propagation in biomechanics10. Identification of model parameter distributions via multilevel Bayesian approachesPart IV. Applications in biomechanical modeling11. Geometric modeling and uncertainties of the vascular system12. Hemodynamics in type B aortic dissection with focus on sensitivity and dimensional analysis13. Uncertainty quantification in patient-specific models of left ventricular mechanics models14. Uncertainty quantification for impedance plethysmography with gradient boosting tree regression