Symmetry of relaxation function and instantaneous elasticity in viscoelasticity (Q2754708)

A proof that the major symmetry property of the relaxation function takes place is performed by considering a particular viscoelastic material, which is instantaneously elastic. By using relevant hypotheses and a sequence of three-dimensional step strain theories, all starting at zero time, it is proved that the relative constitutive functional of linear viscoelasticity describes an elastic instantaneous material. The problem is considered using direct and inverse Fourier transforms for the Boltzmann function.