Читать книгу The Rheology Handbook - Thomas Mezger - Страница 219

The spring immediately aims to elastically step back to its initial shape, and this driving force is causing both components to reach their initial positions finally. However, this step occurs only after a certain period of time. Therefore, due to the presence of the dashpot there is a delayed process going on. But indeed, in the very end the model will show no longer any remaining deformation.

As a result of the phase after removing the load, the re-formation process occurs again as a curved, time-dependent e-function in the γ(t)-diagram, but now of course showing moderately decreasing deformation values. After a sufficiently long period of time the reformation will be completed, i. e. displaying γ = 0 again, like at the beginning of the test.

Summary: Behavior of the Kelvin/Voigt model

After a load-and-removal cycle, these kinds of samples show indeed delayed but complete recovery (re-formation) which fully compensates for the previously occurred deformation. There is a reversible deformation process taking place since such a sample occurs in an unchanged shape in the very end of the test. These kinds of materials behave essentially like a solid, and therefore, they are referred to as viscoelastic solids or Kelvin/Voigt solids.