A numerical study of a biaxial sollicitation to set-up the displacement field measurement of ex vivo mouse skin

The behavior of the skin is an important issue in many applications, but is always not well understood. Nevertheless, skin is well-known to be mainly composed of collagen and has a very hierarchical microstructure that influences its mechanical behavior at different scales. To correlate and to characterize the macroscopic behavior with the microstructure, a bi-axial tensile test coupled with a macroscopic (digital image correlation) and microscopic (second harmonic generation) measurement has been developed. This study aims at presenting the method used to identified the mechanical properties of mice ex vivo skin. A full-field displacement is firstly acquired using digital image correlation (DIC) and, then, a specific finite element model is used to optimize the mechanical properties. The skin is modelled with a Holzapfel hyperelastic behavior which presents the particularity of being strongly based on the microstructure. The purpose of this article is to prepare the identification process. To this aim, a sensitivity approach is developed to choose the configuration with the highest sensitivity. Finally, the displacement and strain field is measured with DIC.