Asymptotic behavior of creep curves in the Rabotnov nonlinear heredity theory under piecewise constant loadings and memory decay conditions

Creep curves produced by the Rabotnov nonlinear hereditary constitutive relation for multi-step uniaxial stress histories are studied analytically under minimal primary restrictions on two material functions of the relation. Dependence of creep curves asymptotic behavior at infinity on material functions properties and loading steps parameters is analyzed. Necessary and sufficient conditions for simulation of the fading memory property are obtained. The key role of a creep function derivative limit value at infinity for plastic strain accumulation rate is shown. A number of inherited properties, peculiarities and additional capabilities of the Rabotnov nonlinear relation are revealed in comparison to capabilities of the linear viscoelasticity relation and the ancestral properties.