When: Wednesday, 28 October 2026, 14:00–16:00
Where: NOVA FCT, Room 3.05, Building VIII
Language: English (interactive Jupyter Notebook demo)
Admission: free, no registration
Organisation: José Xavier (UNIDEMI)
Prof. Stéphane Avril (Sainbiose, Mines Saint-Étienne, INSERM, France) will present on 28 October 2026, at NOVA FCT, the seminar “Optical techniques and inverse methods in soft-tissue mechanics: the Virtual Fields Method”. The session is delivered in English, includes an interactive Jupyter Notebook demo, and is open to the whole UNIDEMI community.
Soft biological tissues, such as the aortic wall, undergo large deformations, behave nonlinearly and anisotropically, and vary from point to point. Classical uniaxial or biaxial tensile tests yield a force–displacement curve, but by Saint-Venant’s principle the stress state is homogeneous only far from the grips, and the information from a single test is limited. Optical full-field measurement techniques address part of this problem by recording displacements and strains over the entire surface, or volume, of the specimen. Extracting constitutive parameters from those fields then requires inverse methods.
The seminar follows this path in four parts: why full-field measurements are needed in soft-tissue mechanics; how they are obtained (DIC, stereo-DIC, OCT, digital volume correlation); how constitutive models are identified, with emphasis on the Virtual Fields Method; and a case study on aortic aneurysm tissue from a bulge test measured by stereo-DIC, with a Python implementation of the Virtual Fields Method (neo-Hookean then Holzapfel).
Stéphane Avril is a full professor at Mines Saint-Étienne, where he co-founded and co-directed the SAINBIOSE laboratory and directed the Centre Ingénierie et Santé. He has held visiting professorships in Austria, the UK and the USA. His work in biomechanics has been recognised with two European Research Council awards: an ERC Consolidator Grant (BIOLOCHANICS, 2015) and an ERC Proof of Concept (2022).
Collaboration with NOVA FCT on aortic biomechanics is long-standing; with the researcher José Xavier he coordinates the PESSOA bilateral cooperation project on computational modelling of ascending thoracic aortic aneurysms.
The initiative is framed by the PESSOA Programme – Portugal–France Bilateral Cooperation (ref. 2024.07108.CBM), funded by FCT, I.P. and Campus France, with the support of UNIDEMI, funded by FCT, I.P. (UID/00667/2025).