Viscoelasticity: Difference between revisions

Revision as of 13:14, 13 August 2025

Revision as of 22:16, 31 August 2025

(7 intermediate revisions by 2 users not shown)

Line 3:

{{Continuum mechanics|cTopic=rheology}}

'''Viscoelasticity''' is a material property that combines both viscous and elastic characteristics. Many materials have such viscoelastic properties. [https://www.viscoelasticity.info/what-is-viscoelasticity/ Especially materials that consist of large molecules show viscoelastic properties]. [[Polymer|Polymers]] are viscoelastic because their [[Macromolecule|macromolecules]] can make temporary [https://www.stevenabbott.co.uk/practical-solubility/polymer-entanglement.php entanglements] with neighbouring molecules which causes elastic properties<ref>{{Cite book |last=Doi |first=M |title=The theory of polymer dynamics |publisher=Oxford University Press |year=1986 |isbn=0198520336}}</ref>. After some time these entanglements will disappear again and the macromolecules will flow into other positions where new entanglements will be made (viscous properties).

A viscoelastic material will show elastic properties on short timescalestime scales and viscous properties on long time scales. These materials exhibit behavior that depends on the time and rate of applied forces, allowing them to both store and dissipate energy.

Viscoelasticity has been studied since the nineteenth century by researchers such as [[James Clerk Maxwell]], [[Ludwig Boltzmann]], and [[William Thomson, 1st Baron Kelvin|Lord Kelvin]].

Line 11:

Several models are available for the mathematical description of the viscoelastic properties of a substance:

* [[Constitutive equation|Constitutive models]] of linear viscoelasticity assume a linear relationship between [[Stress (mechanics)|stress]] and [[Strain (mechanics)|strain]]. These models are valid for relatively small [[Deformation (physics)|deformations]]. only.

* Constitutive models of non-linear viscoelasticity are based on a more realistic non-linear relationship between stress and strain. These models are valid for relatively large deformations.

The viscoelastic properties of polymers are highly temperature dependent. From low to high temperature the material can be in the [https://www.viscoelasticity.info/5-glass-rubber-and-melt-phase/ glass phase, rubber phase or the melt phase]. These [[Phase (matter)|phases]] have a very strong effect on the mechanical and viscous properties of the polymers.

Typical viscoelastic properties are: