Relevance of Indentation Test to Characterize Soft Biological Tissue: Application to Human Skin

This contribution presents a new investigation to identify the viscoelastic parameters of soft biological materials using indentation test. The purpose is to present a new independent method on experimental specificities in order to characterize these materials. The identification was done using inverse analysis based on combining finite element (FE) numerical simulations and experimental indentation tests. By considering soft tissues as an isotropic linear viscoelastic material, we firstly validate our proposed FE model via a comparison between analytic and numerical indentation responses. Secondly, the existence and uniqueness of inverse problem solution based on the comparison of numerical/numerical responses is shown. Finally, we validate the stability of the inverse approach using sensitivity analysis by setting up a design of experiment (DOE) technique which proves the relevance of this proposed method. An application is made on the forearm of human skin and shows performances of this proposed method to identify viscoelastic human skin properties in spherical loading-unloading indentation test. This method can be applied to evaluate other viscoelastic materials.