The Burgers Model is a general model of a viscoelastic material, commonly used to describe a classic creep recovery measurement (see Creep).
The model is a combination of spring and dashpots, arranged as combination of separate component in series and in parallel.
- Springs - indicate an elastic response. When “pulled” under an applied stress load will instantly stretch to a defined length (strain), and recover completely to the initial state when the load is removed. (Should the applied stress be larger than what the spring can absorb, permanent/non-recoverable deformation will occur, see “yield stress”.)
- Dashpots – indicate a viscous response. When “pulled” under an applied stress load will move over time (with a speed dependent the viscosity), and continue to move until the load is removed. There is no recovery when the load is removed and stays permanent deformed.
So, in the Burgers models G1 and η2 are independent in series and model the separate elastic and viscous components of a material.
G2 and η1 are in parallel which mimics the viscoelastic component of a sample where the immediate spring/elastic response is “dampened” (slowed) by the dashpot/viscous component when a load is applied.
With the stress load removed, G2 recovers, but again is dampened by η1, but will recover completely as long as the applied stress is linear, i.e. within the “linear viscoelastic region”.