Rheology and rheometry –
a short introduction
Introduction to Rheology
The genesis of rheology
The term rheology was proposed by E.C. Bingham and M.
Reiner in 1929 for an interdisciplinary field of
material sciences
It derives of the Greek terms for flow ῥεῖ (rhei) and λόγος
(logos) for word (science)
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Introduction to Rheology
The genesis of rheology
Rheology is the science of the deformation and flow
of matter under controlled testing conditions!
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Introduction to Rheology
The genesis of rheology
M. Reiner also proposed the ancient
aphorism panta rhei* (everything flows) as
the motto of the Society of Rheology.
The Society of Rheology was officially formed
on December 9, 1929.
http://www.rheology.org/sor
*Heraclitius (Simplicius)
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Introduction to Rheology
A fundamental principle in rheology
Panta rhei! But does really everything flow?
Well, it depends!
How long do you want to wait?
Deborah* Number =
Time of Relaxation
Time of Observation
*after prophetess Deborah, Judges 5:5
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Introduction to Rheology
A fundamental principle in rheology
Everything flows!
Example 1: The visco-elastic behavior of Silly Putty
Bouncing ball
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Gravity acting over time
Introduction to Rheology
A fundamental principle in rheology
Everything flows!
Example 2: The glass windows of the Cathedral of Chartres in France
Gravity
1200
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2011
Images taken from wikipedia
Definition of basic rheological parameters
Viscosity and viscous flow
“The resistance which arises from the lack of
slipperiness of the parts of the liquid, other
things being
equal, is proportional to the velocity with
which the parts
Sir Isaac Newton
of the liquid are separated from one another.”
1642 - 1727
Philosophiae Naturalis Principia Mathematica 1687
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Definition of basic rheological parameters
Viscoelasticity
“The power of any spring is in the
same proportion with the tension
thereof.”
Robert Hooke
1635 - 1703
Image taken from wikipedia
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True Theory of Elasticity 1678
Definition of basic rheological parameters
Viscoelasticity
Viscosity
Elasticity
(Dashpot)
(Spring)
Real Systems
Rotation and Oscillation
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Rotation and Oscillation
Any questions ?
Thank you for your attention
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