A numerical-experimental method to characterize the non-linear mechanical behaviour of human skin.

BACKGROUND/AIMS Human skin is a complex tissue consisting of several distinct layers. Each layer consists of various components with a specific structure. To gain a better insight into the overall mechanical behaviour of the skin, we wish to study the mechanical properties of the different layers. A numerical-experimental method was developed to characterize the non-linear mechanical behaviour of human dermis. METHODS Suction measurements at varying pressures were performed on the volar forearm skin of 10 subjects aged 19-24 years old. Deformation of dermis and fat during suction was measured using ultrasound. The experiment was simulated by a finite element model exhibiting extended Mooney material behaviour to account for the non-linear stress-strain relationship. An identification method is used to compare the experimental and numerical results to identify the parameters of the material model. RESULTS C10, dermis was found to be 9.4 +/- 3.6 kPa and C11, dermis to be 82 +/- 60 kPa. A first rough estimate of C10, fat was 0.02 kPa. CONCLUSIONS The resulting finite element model demonstrated its ability to describe the response of the skin to suction at various pressures. In the future, this method can be used to characterize the mechanical behaviour of different skin layers using various aperture sizes and to characterize the skin behaviour under various loading conditions.