Studies on nonlinear visco-elastic spherical waves by characteristics analyses and its application

Based on the ZWT nonlinear visco-elastic constitutive model, the governing equations for nonlinear visco-elastic spherical waves are formulated. By use of characteristics method, the problem of solving those five partial differential equations is reduced to solve five ordinary differential equations along 3 sets of characteristics. Numerical results are given, illustrating the non-ignored viscosity effects and nonlinear effects. The attenuation law for visco-elastic spherical shock wave is analytically derived. A new inversion method is proposed, by which the high-strain-rate visco-elastic parameters could be inversely determined from a series of particle velocity profiles measured in a spherical wave experiment.