A nonlinear model and a new suction device for the evaluation of skin elasticity

A new approach to quanta the viscoelastic behavior of human skin on mechanical stress is proposed. The apparatus for multiaxial tensile tests consists of a suction device to extend the skin and an optical image processing system to observe the test area. Image processing techniques are used to calculate displacement vector fields and to detect the two-dimensional deformation state of the skin. A nonlinear model built up of springs, dashpots and a St.-Venant-Body, is used to characterize the stress-strain-time relationships and to obtain a set of parameters, which represent the instantaneous elasticity. the delayed elasticity and the viscosity of skin on loading.