Rheology and rheometry a short introduction

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Rheology and rheometry a short introduction

Transcript of Rheology and rheometry a short introduction

Rheology and rheometry –

a short introduction

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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

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Thank you for your attention

Any questions ?