Click on image to view larger version.
Figure 4. Relaxation and creep function of (A) Maxwell, (B) Voigt, and (C) Kelvin model (standard linear solid). Maxwell’s model and Voigt’s model consist of only two elements, which are a linear spring with a spring constant µ and a dashpot with a coefficient of viscosity 
, whereas Kelvin’s model is composed of a combination of two springs and a dashpot. A linear spring produces an instantaneous deformation proportional to the stress. A dashpot produces a velocity proportional to the stress at any instant.
