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Introduction to 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)
The genesis of rheology
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The genesis of rheology
Introduction to Rheology
Rheology is the science of the deformation and flow
of matter under controlled testing conditions!
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M. Reiner also proposed the ancient
aphorism panta rhei* (everything flows) as
the motto of the Society of Rheology.
The genesis of rheology
http://www.rheology.org/sor
The Society of Rheology was officially formed
on December 9, 1929.
Introduction to Rheology
*Heraclitius (Simplicius)
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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
Introduction to Rheology
*after prophetess Deborah, Judges 5:5
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A fundamental principle in rheology
Everything flows!
Example 1: The visco-elastic behavior of Silly Putty
Introduction to Rheology
Bouncing ball Gravity acting over time
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A fundamental principle in rheology
Images taken from wikipedia
Everything flows!
Example 2: The glass windows of the Cathedral of Chartres in France
1200 2011
Gravity
Introduction to Rheology
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Sir Isaac Newton
1642 - 1727
“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
of the liquid are separated from one another.”
Philosophiae Naturalis Principia Mathematica 1687
Definition of basic rheological parameters
Viscosity and viscous flow
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Robert Hooke
1635 - 1703
“The power of any spring is in the
same proportion with the tension
thereof.”
True Theory of Elasticity 1678
Viscoelasticity
Definition of basic rheological parameters
Image taken from wikipedia
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(Spring)
Definition of basic rheological parameters
Viscoelasticity
Rotation and Oscillation Rotation and Oscillation
Elasticity
Real Systems
(Dashpot)
Viscosity