STRUCTURAL GEOLOGY HATCHER 6

Question 1

Three end members of deformatio

Answer 1

Elastic
Plastic
Viscous

Question 2

Objects with materia memory

Answer 2

Elastic

Question 3

permanent strain that occurs without loss of cohesion and is the result of rearrangement of chemical bons in crystal lattices in minerals by one or more DISLOCATION CREEP MECHANISMS

Answer 3

Plastic

Question 4

Behaviour of fluids such as water or magma or any other substances with LITTLE INTERNAL STRUCTURE and is perasive, permanent and involves dependence of strain rate on stress

Answer 4

Viscous

Question 5

Another term for elastic behaviour

Answer 5

HOOKEAN

Question 6

This implies failure in the elastic range particularly in breaching the elastic limit

Answer 6

Brittle behaviour

Question 7

this best describes LINEAR ELASTIC BEHAVIOR in an isotropic Homogenous material and states that elastic strain is directly proportional to the stress applied

Answer 7

Hooke’s Law (Robert Hooke)

Question 8

Mathematical equation of Hookes Law

Answer 8

Applied stress = Youngs modulus * strain

Question 9

Therfore what is the formula for the elastic constant aka youngs modulus?

Answer 9

E= Stress/Strain = F/A / (L1-L0)/L0

Question 10

Elastic behaviour under shear stress

Answer 10

Shear stress = Rigidity Moduls* Shear Strain

Question 11

Thus rigidity modulus is equal to

Answer 11

G = Shear stress/Shear strain

Question 12

This is where the stress strain curve changes slope abruptly which denotes area where hooke’s law is no longer applicable and beyond which the material begins to undergo permanent defomrtaion or ruptures

Answer 12

Yield point/Elastic Limit

Question 13

This is the highest point in a stress strain curve

Answer 13

Ultimate strength

Question 14

Rocks theoretically begins to fracture at this point or value of ultimate strength

Answer 14

Half of the ultimate strength

Question 15

A measure of compressibility of PR = - E1 (Lengthening )/ E3 (Change in h (- shorthening) which is always positive

Answer 15

Poissons ratio

Question 16

Poission’s ratio of water and its implication

Answer 16

0.5 = incmpressible

Question 17

Possons of Halite

Answer 17

<0.5 low compressibility

Question 18

Possons of less than 0.5 means

Answer 18

VOLUME Decreased

Question 19

Formula of possons using Vp compressional and Vs Shear wave velocity

Answer 19

0.5 [1- (1/(Vp/Vs)^2-1)]

Question 20

Beyond elastic limits the behaviour of solid and liquids respectively are

Answer 20

Solid: Plastic = liquid: Viscous

Question 21

Stationary fluids that does not transmit shear stress

Answer 21

Perfect Fluids

Question 22

Fluids in which there is linear proportionality between the differential stress or shear stress and shear strain rate

Answer 22

Newtonian Fluids

Question 23

Si unit for Viscosity?

Answer 23

Poise

Question 24

Equivalent of poise to stress units of Pa

Answer 24

10 poise = 1 Pa*s

Question 25

Viscosity is

Answer 25

Differential stress/shear strain rate

Question 26

Shear stress in fluids exists only when they are in?

Answer 26

Motion

Question 27

aka ideal plastic behaviour that begins at yieald point

Answer 27

Saint Venant Behaviour
(Adhemar Jean Claude Barre de Sain Venant)

Question 28

This pertains to the process when material increases resistant to deformatio as strain increases after the yield point

Answer 28

Strain hardening

Question 29

This pertains to process when material decreases resistance to deformation as strain increases

Answer 29

Strain Softening

Question 30

aka of elastiviscous behaviour

Answer 30

Maxwell Behaviour

Question 31

Therfore what is the formula for the elastic constant aka youngs modulus?

Answer 31

Total shear strain = elastic shear strain + viscour shear stran

Question 32

Suggested term for materials that deform like fluids (viscous strain is 100x the elastic strain)

Answer 32

Rheid

Question 33

The phenomenon when Rocks behaviour vary in space and time by concentration of defromation into specific parts of a rock mass by different behaviour or mechanism

Answer 33

Strain Partioning