Viskoelastiskviskoplastisk

Viskoelastiskviskoplastisk describes materials that exhibit both viscoelastic and viscoplastic behavior. Viscoelastic materials show time-dependent deformation and stress relaxation, meaning their response to applied stress depends on how long the stress is applied. They can also recover their original shape after the stress is removed, similar to a spring. Viscoplastic materials, on the other hand, undergo permanent, irreversible deformation when the applied stress exceeds a certain yield stress. This deformation is also time-dependent, with strain rate being a function of stress.

A viskoelastiskviskoplastisk material combines these characteristics. When a stress is applied, it will initially deform elastically, much like a spring. If the stress is below a certain threshold, the material may also exhibit some time-dependent recovery upon unloading, characteristic of viscoelasticity. However, if the applied stress exceeds a yield point, the material will begin to deform permanently, and this permanent deformation will also be influenced by time and strain rate, exhibiting viscoplasticity. Upon unloading after exceeding the yield stress, a portion of the deformation will be recovered (elastic and some viscoelastic recovery), but a permanent set will remain due to the viscoplastic component. This dual behavior makes these materials complex to model and analyze, finding applications in areas like polymers, biological tissues, and certain geological formations where both energy dissipation and permanent deformation under load are significant.