Determination of the Creep Parameters of Linear Viscoelastic Materials

Abstract

Creep process of linear viscoelastic materials is described by the integral equation of Boltzmann-Volterra in which creep kernel is approximated by Rabotnov’s fractional exponential function. The creep equation contains four unknown parameters:α, singularity parameter;β, fading parameter;λ, rheological parameter; andε0, conditionally instantaneous strain. Two-stage determination method of creep parameters is offered. At the first stage, taking into account weak singularity properties of Abel’s function at the initial moment of loading, parametersε0andαare determined. At the second stage, using already known parametersε0andα, parametersβandλare determined. Analytical expressions for calculating these parameters are obtained. An accuracy evaluation of the offered method with using experimentally determined creep strains of material Nylon 6 and asphalt concrete showed its high accuracy.