Property ModellingTheoretical aspects of the testing of elasto-viscoelastic-viscoplastic materials

Through numerical simulation, a material with simultaneous, parallel elastic, viscoelastic and viscoplastic deformation characteristics has been studied. The main aim of this research was to devise experimental means of isolating the component stress contributions, thus facilitating internal variable calculation for constitutive modeling. Component stress contributions from each of the three deforming modes as well as subset separation of viscous, yield, isotropic and kinematic hardening stresses for viscoplasticity are treated. During the study, several shortcomings of current isolation methodology including relaxation and back-stress calculation techniques have been discovered. The methodology within, addresses these and various other complexities involved with the testing of time dependent, nonlinear materials.