Mechanical Properties of Solids Flashcards

You may prefer our related Brainscape-certified flashcards:
1
Q

Deforming Force

A

A force which changes the size or shape of a body

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

Elasticity

A

Property of body being able to regain original size and shape after the removal of deforming force

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

Perfectly elastic

A

Body regains its original size and shape completely and immediately after the removal of deforming force

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

Plasticity

A

If a body does not regain its orginal size and shape even after the removal of deforming force

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

Equilibrium Separation

A

For some particular separation (r), potential energy is minimum and interatomic force is zero

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

Explain elastic behaviour in terms of interatomic force

A
  1. When interatomic r is large, potential energy is negative, interatomic force is attractive
  2. Becomes minimum at equilibrium separation
  3. When separation below r, potential energy increases and interatomic force is repulsive
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

Strain

A

Ratio of change in any dimension produced in the body to original dimension
Strain = Change in dimension / Original dimension

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

Stress

A

Internal restoring force setup per unit area of cross - section of the deformed body
Stress = Applied Force / Area

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

Longitudinal strain

A

Increase in lenth per unit original length
= delta l / l

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

Volumetric Strain

A

Change in volume per unit orignal volume
= delta V / V

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

Shear strain

A

Angle theta through which a face originally perpendicular to the fixed face turned on applying tangential deforming force
= Relative displacement between 2 parallel planes / Distance between parallel planes

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

Elastic limit

A

Maximum stress within which the body completely regains its original size and shape after the removal of deforming fortce

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

Hooke’s Law

A

Extension in a wire is directly proportional to the load applied
Stress / Strain = Constant

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

Modulus of elasticity

A

Ratio of stress to the corresponding striain, within the elastic limit
E = Stress / Strain

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

Young’s Modulus of elasticity

A

Within the elastic limit, ratio of longitudinal stress to the longitudinal strain

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

Young’s Modulus Formula

A

Y = [F / pi (r^2)] * [l / delta l]

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

Proportional limit

A

Highest stress at which stress and strain are directly proportional

18
Q

Yield strength

A

Point at which the material transforms from elastic to plastic

19
Q

Permanent Set

A

Deformation that stays in the material after the applied stress is removed

20
Q

Elastic Hysteresis

A

Difference between strain energy required to generate a given stress and material’s elastic energy

21
Q

Tensile strength

A

Maximum load to which the wire may be subjected by slowly increasing the load to the original area of cross-section

22
Q

Fracture point

A

The fracture point is the point of strain where a material physically separates or breaks apart. It is the maximum strain value at which a material can withstand stress before failing or rupturing

23
Q

Young’s modulus of experimental wire

A

Y = Stress / Strain
= L / (pi)r^2 tan theta

24
Q

Elastomers

A

Materials which can be elastically stretched to large values of strain

25
Q

Plastomers

A
  • Behaviour having both elastic and plastic behaviour
  • Elasticity and plasticity
26
Q

Bulk’s Modulus of elasticity

A

Ratio of normal stress to the volumetric strain

27
Q

Bulk’s modulus of elasticity formula

A

k = - F / A * V / delta V
= - pV / delta V

28
Q

Compressibility

A

The reciprocal of the bulk modulus of a material

29
Q

Modulus of rigidity / Shear modulus

A

Ratio of tangential stress to shear strain

30
Q

Modulus of rigidity formula

A

F / A * l / delta l

31
Q

Why is shear modulus of a material considerably smaller than Young modulus

A

Easier to slide layers of atoms of solids over one another than to pull them apart or to squeeze them close together

32
Q

Elastic after effect

A

Delay in regaining the original state by a body on the removal of the deforming force

33
Q

*

Elastic fatigue

A

Defined as loss in strength of a material caused due to repeated alternating strains to which the material is subjected

34
Q

PE stored per unit volume of a stretched wire

A

U = 1/2 Young’s Modulus * strain^2

35
Q

Total PE

A

u = 1/2 * Y * strain^2 * volume
u = 1/2 * F * delta l

36
Q

Poisson’s ratio

A

Within the elastic limit, the ratio of lateral strain to the longitudinal strain

37
Q

Poisson’s formula

A

sigma = - (l / D) * (delta D) / (delta l)

38
Q

Relation between modulus of rigidity and Young’s Modulus

A

G = Y / 3

39
Q

A sphere contracts in volume by 0.01% when taken to the bottom of sea 1km deep. Find bulk modulus given density as 10^3 kgm^-3

A

9.8 * 10^10 Nm^-2

40
Q

Poisson’s ratio fo a material of a wire whose volume remains constant under an external normal stress

A

V = pi (D^2 / 4) * l
We know differentiation gives 0 (as volume is constant)
0 = (pi)(l)/4 * 2D * dD + (pi)(D^2)/4 * dl
-ldD = Ddl or dD/D = -1/2 dl / l
sigma = -(dD / D) / dl / l = +1/2 (SIGN watch out)

41
Q

Relation between Y, k, shear modulus, poissson’s ratio

A

(9/Y) = 3 / (shear) + 1 / k
Y = 2 (shear) ( 1 + poisson)

42
Q

Relation between elasticity and compressibility

A

More incompressible = Less strain = More elastic