Nonlinear viscoelastic material property estimation for lower extremity residual limbs

Human soft tissue is known to exhibit a nonlinear stress-strain relationship, as well as time dependent behavior such as creep and relaxation. The ability of computer models to simulate the response of lower extremity soft tissue loading is dependent on how well the tissue material properties approximate actual tissue behavior. Axisymmetric finite element models of residual limb soft tissue in the vicinity of an indentor test site were constructed to estimate parameters of a viscoelastic material formulation. A two-term Prony series viscoelastic material model approximates the relaxation and creep behavior of the lower extremity residual soft tissue in compression fairly well