Creep and Stress Relaxation for Four-Element Viscoelastic Solids and Liquids

creep

relaxation

four-element model parameters

k

1

2.

η

1

1.

k

2

1.

η

2

0.5

axes maxima

t

max

2.

strain

max

4.

stress

max

3.

This Demonstration plots the creep curve under unit stress and the stress relaxation curve at constant unit strain of four-element solid and liquid mechanical analogs composed of two springs and two dashpots in different arrangements. For creep, the solid viscoelastic model is composed of two Kelvin–Voigt elements in series, and the liquid model is composed of a Maxwell and a Kelvin–Voigt element in series (the Burgers model). For relaxation, the solid model is composed of a Kelvin–Voigt and a Maxwell element in parallel, and the liquid model is composed of two Maxwell elements in series. Qualitatively, the generated creep and relaxation curves are similar to those of other four-element solid and liquid models. They show that the solid has asymptotic strain in creep and asymptotic residual stress in relaxation, while the liquid deforms indefinitely in creep and asymptotically reaches zero residual stress in relaxation.