Page 275 - Mechanics of Asphalt Microstructure and Micromechanics
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F inite Element Method and Boundar y Element Method   267


                                        Viscoelasticity
                                                ε =  ε +  ε i
                                                    e
                                         σ V
                                                   V   V







                                                  ε =  ε e  +  ε p
                                          σ EP
                                                      EP  EP
                                        Elastoplasticity
                                         σ =  σ  +  σ
                                           T
                                               EP  V      ε

                                                a. Constitutive Model in Total Stress and Strain
                                         Viscoelasticity
                                       Δ σ V  Δε =  Δε +  Δε V i
                                                   e
                                                   V








                                      Δσ EP    Δε =  Δε EP  +  Δε EP
                                                     e
                                                          p
                                         Elastoplasticity
                                     Δσ =  Δσ  +  Δσ      Δε
                                        T
                                             EP   V
                                                   b. Constitutive Model in Incremental Stress and Strain
                             (where V denotes viscoelasticity component, EP denotes elastoplasticity component)
              FIGURE 8.5  The SHRP viscoplasticity model.


                 Thus,
                                         C ijkl  = C ijlk  = C jikl  = C klij    (8-74)
                 The detailed derivation of the elasticity tensor was not presented.

              The Viscous Component
                                        .       n
                                        ε = ( −  b  n  ) −1 ζ∂ W( )              (8-75)
                                                         ε
                                                          e
                                                    −1
                                         i
                                            1
                                                      e
                                                      ε
                                               ρ
                 Equation (8-75) basically states that the current inelastic strain rate is proportional
              to the current stress.
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