The Voight model is best model for the response shown in (c). The step increase in stress is applied to a spring constrained by the viscous damper. The spring only reaches its equilibrium length under the applied stress after some time. Upon removal of the stress, the spring is prevented from immediately returning to its original length by the damper and reaches zero extension with the same relaxation time as that shown during loading.

The Maxwell model is a better description of creep behavior in a viscoelastic material. If a step strain is applied to the system a stress condition is established in the spring. If the strain is kept constant, the series damper moves and relaxes the stress in the spring. Removal of the external interaction leaves the system in a strained condition.