On the dynamic system identification of the response behaviour of linear viscoelastic materials

In this paper, the basic idea of a dynamic system identification of the theological response of linear viscoelastic materials, as presented by the authors in reference, 8 is extended whereby the instantaneous response of the linear viscoelastic material is taken into consideration through the Laplace initial theorem. A relation is established between the creep, or relaxation, function and the transfer function of the dynamic system. The analytical model of the above mentioned reference is modified to accommodate, in the transfer function of the system, the discontinuity of creep, or relaxation, function at time equal to zero. A discrete-time system analysis is introduced to determine the order and parameters of the modified model from dynamic experiment measurements. The numerical examples given show that the analytical procedure leads to an accurate and efficient model.