Lecture 3

Question 1

Define Rheology

Answer 1

The study of how materials flow (deform).

Describe the “cause and effect” relationship between dynamic quantities (stress) and kinematic quantities (strain or strain rate)

Question 2

Describe Elasticity

Answer 2

Natural or artificial causes that produce instantaneous strain which propagates away from the source

Hookean

Rheological behaviours that applies to solids

Question 3

Describe Plasticity

Answer 3

Non-reversible change in shape

Relevant to both solids and fluids

Question 4

Describe Viscosity

Answer 4

A given shear stress produces a flow at a constant rate (strain rate)

The stickiness if a fluid

High viscosity = stickier (like syrup)
Lower Viscosity = less sticky (like water)

Newtonian

Rheological behaviour that applies to fluids

Question 5

Viscosity in Gases

Answer 5

Independent on pressure

Increase as temp increases

Question 6

Viscosity in liquids

Answer 6

Independent of pressure (Except very high pressure)
Viscosity decreases with increasing temperature
Viscosity in liquids several magnitudes higher than in gases