A note on aging of a viscoelastic cylinder

Rajagopal and Wineman [K.R. Rajagopal, A.S. Wineman, A note on viscoelastic materials that can age, Internat. J. Non-Linear Mech. 39 (2004) 1554–1574] showed that the stress relaxation due to viscoelastic effects and aging are distinctly different, in that the stress relaxation due to aging is geometry dependent. Here, I include the effect of stress relaxation in a Kelvin–Voigt solid, that cannot stress relax due to viscoelastic effects, due to aging. I also show that the viscoelastic contribution of the total torque and the normal force is such that space and time are separable, while the same cannot be said about the contribution due to aging.