Definition of Rheology : Irreversible or not?

In summary: It is often used to describe stress-strain processes, both time dependent and irreversible. However, some writers and groups use it to cover processes outside of this definition, which is not appropriate. This may be due to a lack of alternative terms to describe these stress-strain relations. In summary, rheology is the study of stress-strain relations and flow of materials, including both reversible and irreversible processes. However, it is important to use the term accurately and not extend its definition beyond its scope.
  • #1
hizballah_arham
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I found definition of rheology to describe stress-strain processes of flow which irreversibly with time. But some of writers and groups use this term to describe reversible processes too. So what is exactly the true definition of rheology in fluid mechanics?
In Agricultural Process Engineering(Third Edition) by S.M. Henderson and R.L. Perry, Rheology is described as "... the science that considers stress-strain relations where flow proceeds irreversibly with time. Creep in metals and concrete and the strength properties of fruits and vegetables are examples. Strictly recognized, thixiotropic and rheopetic fluids are not rheological materials because there is no permanent deformation. Unfortunately, many writers and groups use the term rheology to include a variety of stress-strain processes that may or may not be time dependent or irreversible. The engineer should be aware that the term is frequently used to cover processes outside those in the definition."

My question is, does the definition of rheology truly only for irreversible processes when it's first stated? So does that mean the use of it for reversible processes it's not appropriate? Then why some writers and groups still using it despite that mistake, is it because there's no other term to be used to describe stress-strain relations of flow?

Just wanted to hear about your opinion and discuss about the topic. Thank you for clicking the thread!
 
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  • #2
Rheology includes both reversible and irreversible material deformations. So it includes purely elastic material deformations. It is defined as the science of deformation and flow of materials.
 
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FAQ: Definition of Rheology : Irreversible or not?

1. What is rheology?

Rheology is the study of the flow and deformation of matter, particularly liquids and soft solids.

2. What is meant by "irreversible" in rheology?

In rheology, "irreversible" refers to a material's inability to return to its original state after being subjected to a deformation or flow.

3. How is rheology relevant in scientific research?

Rheology is important in many fields of science, including materials science, geology, biology, and engineering. It helps us understand the behavior of complex fluids and soft materials, and can be used to develop new materials and improve existing ones.

4. Can rheology be used to study non-Newtonian fluids?

Yes, rheology is particularly useful in studying non-Newtonian fluids, which do not follow the simple linear relationship between stress and strain that Newtonian fluids do.

5. What are some common techniques used in rheology experiments?

Some common techniques used in rheology experiments include rotational and oscillatory shear rheometry, dynamic mechanical analysis, and capillary rheometry. These techniques measure the response of a material to different types of deformation or flow.

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