Estimation of quasi-linear viscoelastic material parameters using nonlinear optimization method

The soft tissues are considered as complex materials which are difficult to be modeled due to their nonlinear geometric and material properties, their multilayer structures, large displacements, anisotropic, nonhomogenous and viscoelastic material properties. This study focuses on the error minimization and converge problem in predicting the non-unique material parameters of quasi-linear (QLV) integral form by Fung [5] which is used in modeling viscoelastic material properties of soft tissues. The solution is improved by using refined nonlinear optimization method.