Public thesis defense Guillaume Duprez - IMMC
sst |
How biomechanics helps interpret fingertip deformation
Wednesday September 16th, 2026 - 4:30pm - Auditorium BARB92 - Place Sainte-Barbe1, 1348 Louvain-la-Neuve
Our fingertips are remarkable sensory organs that let us interact safely with our environment. Tactile sensors embedded below the skin surface encode the deformation of the surrounding tissues into neural signals. These signals travel to the brain to allow dexterous object manipulation. Capturing subsurface strains in the fingertip is therefore key to understanding touch. Such strains, however, are difficult to probe in vivo at the depth where the tactile sensors are located.
The numerical model of fingertip deformation developed in this thesis accounts for the contrasted mechanical responses of cutaneous and subcutaneous tissues. The anisotropy induced by collagen fiber networks had not been considered in previous fingertip models, despite substantial histological and experimental evidence. Both features were described within an anisotropic hyperelastic framework. The 2D simulations were run under generalized plane-strain or axisymmetric conditions, depending on the targeted experimental observations.
The model was assessed against experimental measurements of fingertip contact at two length scales. At the macroscale, collagen anisotropy improves the reproduction of the contact area, the pulp expansion, and the surface deflection profile. At the microscale, anisotropy and tissue heterogeneity influence the development of the surface strains. Optical coherence tomography images capturing the deformation of the outermost skin layer show that the model also yields a realistic prediction of the skin thickness evolution during contact. The results identify the collagen fiber networks as structural components that shape the mechanical response of the fingertip.
Jury members
Prof. Laurent Delannay (UCLouvain), Supervisor
Prof. Benoît Delhaye (UCLouvain), Supervisor
Prof. Hadrien Rattez (UCLouvain), Chairperson
Prof. Philippe Lefèvre (UCLouvain), Secretary
Prof. Cédric Laurent (Université Lorraine, France)
Dr. Hannes Saal (Sheffield University, UK)