Professor for Strength of Materials and Computational Mechanics
Dept of Civil Engineering
Vienna University of Technology (TU WIEN) Vienna, Austria
Abstract: Traditionally, the realms of hard and soft tissue biomechanics are strictly separated: hard tissue biomechanics is typically based on elasto-plastic or elasto-damage formulations in the small strain regime, while soft tissue biomechanics has its roots in hyperelastic rubber modeling. Both of these two traditional approaches face the challenge of highly scattering material parameters, which rarely allow for reliable predictions of untested situations.
In the hard tissue realm, this challenge has been met with the advent of engineering micromechanics in the early 2000s. Key ingredients of this success were the hierarchical sequencing of traditional homogenization schemes such as two-phase Mori-Tanaka and self-consistent schemes, the extension from two-phase to multi-phase systems, and the consideration of eigenstrains and their upscaling characteristics, which paved the way towards a unified vision of bone multiscale biomechanics,encompassing poro-elasticity, poro-plasticity, and creep; all based on a few “universal” mechanical properties of bone’s elementary components: collagen, hydroxyapatite, and water.
Can this success be repeated also for soft tissues? The lecture will give an affirmative answer, based on recently developed theoretical tools allowing for the modeling of load-induced changes in the tissue micro-morphology, as it evolves under large strains at different observational levels.
Biosketch: Dr. Christian Hellmich, M.ASCE, F.EMI, Full Professor at the Department of Civil Engineering of the Vienna University of Technology (TU Wien), is the director of the Institute for Mechanics of Materials and Structures. At TU Wien, he received his engineering, PhD, and habilitation degrees (in 1995, 1999, and 2004, respectively). From 2000 to 2002, he was a Max Kade Postdoctoral Fellow in the Department of Civil and Environmental Engineering at the Massachusetts Institute of Technology. He is well known for his well-validated material and (micro)structural models, in terms of theoretical foundations and applications to concrete, soil, rock, wood, bone, and biomedical
implants, up the structural level (tunnels, pipelines, biological organs such as the skeleton) - with complementary experimental activities if necessary. On these topics, he has directed various interdisciplinary and multinational research consortia, and he has published more than 125 papers in international refereed scientific journals.