SOM Interview and Viva
Questions
& Answer
1.
Define
Compressive Stress And Compressive Strain?
The stress-induced in a body, when
subjected to two equal and opposite pushes, as a result of which there is a
decrease in length, is known as compressive stress. The ratio of increase in
length to th original length is known as compressive strain.
2.
Define
Shear Stress And Shear Strain?
The stress-induced in a body, when
subjected to two equal and opposite forces, which are acting tangentially
across the resisting section as a result of which the body tends to shear off
across the section is known as shear stress and corresponding strain is known
as shear strain.
3. What Is Sketch A Composite Bar?
A bar made up of two or more bars of equal length but of
different materials rigidly fixed with each other behaving as one unit for
extension or for compression when subjected to an axial tensile or compressive
load is called a composite bar.
4. Define Poisson’s Ratio?
The ratio of lateral strain to the linear strain is a
constant for a given material when the material is stressed within the elastic
limit. This ratio is Poisson’s ratio and it is generally denoted by 1/m or µ.
Poisson’s ratio 1/m = µ = linear strain/ lateral strain
5. Write The Relationship Between Modulus Of Elasticity,
Modulus Of Rigidity And Poisson’s Ratio?
The relationship between modulus of elasticity, modulus
of rigidity and Poisson’s ratio is given by
E = 2C (1+ 1/m)
E=Modulus of elasticity
C=Modulus of rigidity
1/m = Poisson’s ratio
6. What Is State Hooke’s Law?
Hooke’s law is stated as to when a material is loaded within
the elastic limit, the stress is proportional to the strain produced by stress,
or Stress/strain=constant. This constant is termed as modulus of elasticity.
7. Define Stress And Strain?
Stress: The force of resistance per unit area, offered by
a body against deformation is known as stress.
Mathematically stress is written as
f=P/A
Where f= stress
P=external force or load
A=cross-sectional area.
Unit of stress: stress is represented in N/m2
Strain: The ratio of change in dimension to the original dimension
when subjected to an external load is termed as strain and is denoted by e. It
has no unit.
8. Define Modulus Of Rigidity?
The ratio of shear stress to the corresponding shear
strain, when the stress is within the elastic limit, is known as modulus of
rigidity or shear modulus and is denoted by C or Gor N
Shear stress / Shear strain = q / ?
9. Define Modulus Of Elasticity?
The ratio of tensile stress or compressive stress to the
corresponding strain is known as modulus of elasticity or young’s modulus and
is denoted by E.
stress / strain = E
10.Define Bulk Modulus?
When a body is subjected to uniform direct stress in
all the three mutually perpendicular directions, the ratio of the direct stress
to the corresponding volumetric strain is found to be a constant is called as
the bulk modulus of the material and is denoted by K.
K =
direct stress / volumetric strain = P/A / dv/v
11. Define Longitudinal Strain And Lateral Strain?
Longitudinal strain: the longitudinal strain is defined as
the deformation of the body per unit length in the direction of the applied
load.
Longitudinal strain= dL/L
Where L= length of the body.
P= tensile force acting on the body
dL= increase in the length of the body in the direction
of P
12. Define Factor Of Safety?
defined as the ultimate stress to the working stress
or permissible stress.
The factor of safety = ultimate
stress / permissible stress
13. State The Two Conditions Employed In Solving A
Composite Bar Subjected To An Axial Load?
Two conditions employed in solving a composite bar are
P=f1A1 + f2A2
e= f1/E1 + f2/E2
Where P =total load
e= strain
f1 and f2 = stress set up in the respective materials.
E1 and E2 = modulus of elasticity of the respective
materials.
Give the relationship between modulus of elasticity,
modulus of rigidity and bulk modulus.
E = 9KC / 3K+C
Where
E= young’s modulus
K= bulk modulus
C= rigidity modulus
14. What Is Stability?
Stability may be defined as an ability of a material
to withstand high load without deformation.
15. Give Example For Gradually Applied Load And Suddenly
Applied Load?Example for the gradually applied load
When we lower a body with the help of a crane, the body
first touches the platform on which it is to be placed. On further releasing
the chain, the platform goes on loading till it is fully loaded by the body.
This is the case of the gradually applied load.
16. The impact
strength of a material is an index of its toughness
17. In brittle material, normally, breaking stress is
equal to ultimate stress
18.Thermalstrain of a body does not depend on length.
19. Thermal change of length of a metal is directly proportional to its thermal
coefficient.
20. In ductile material ultimate stress is higher than
nominal breaking stress but lower than true breaking stress
21. The
property of a material that allows it to be drawn into a smaller section is
called
ductility
22. The loss
of strength in compression due to sustained loading is known as
creep
23. The
maximum strain energy that can be stored in a body is known as
proof resilience
24. The total
strain energy stored in a body is termed as
resilience
25. Proof stress is stress causing a specific permanent
deformation usually 0.1% or 0.2%.
26. Thermal strain caused in a Reinforced composite
body due to change in temperature will be same magnitude
27. Within Elastic limit Actual Stress is less than
Nominal Stress
28. The energy
absorbed by a body, when it is strained within the elastic limit, is known as
resilience
29. Value of factor of safety is greater than 1
30. Hooke’s Law is truly valid up to the proportional limit
31. In ductile material nominal breaking stress is lower
than true breaking stress
32. Mild Steel is widely used in Reinforced Concrete
because the Thermal coefficient is almost equal to concrete
33. In tension test Actual Stress is equal to or greater
than Nominal Stress
34. For mild steel, the Yield stress is nearly equal to
elastic stress
35. Metals
used for the suspension system and spring action should have high
resilience
36. Mild Steel is tougher than High Tensile steel
37. To prevent fatigue failure, the stress developed
should be kept below the endurance limit
38. In brittle
metals, the failure surface is at 90 angles to the direction of load.
39. Direct Stress is caused due to axial loads
40. Shear stress acts parallel to section
41. Wood is an example of orthotropic material
42. Shear stress causes angular deformation
43. In a shaft
rotated by a couple, the shear force varies From zero at the centre to a maximum at the circumference
44. The shape of
the bending moment diagram over the length of a beam, having no external load,
is always Linear
45. The stress at
which extension of a material takes place more quickly as compared to the
increase in load is called Yielding point
46. A simply
supported beam of span ‘L’ carries
a uniformly distributed load ‘W’. The maximum
bending moment ‘M’ is WL/8
47. A member
which does not regain its original shape after removed of load producing
deformation is said Plastic
48. When a rectangular beam is loaded transversely, the maximum compressive stress
develops on Top fibre
49. Columns of
given length, cross-section and material have different values of buckling
loads for different end conditions. The strongest column is one whose Both the ends are fixed
50. The centre of the gravity of a uniform lamina lies at The midpoint of its axis
51. The maximum twisting moment a shaft can resist is the product of the permissible shear
stress and Polar modulus
52. The deflection
of any rectangular beam simply supported, is Inversely proportional to the
cube of its depth
53. A beam is
said to be of uniform strength, if Bending stress is the same
throughout the beam
54. The ratio of
limiting friction and normal reaction is known as the Coefficient of friction
55. In a solid the arch, shear force acts Perpendicular to the axis of
arch
56. Along
vertical member, subjected to an axial compressive load, is called A column
57. The property
of a material by which it can be drawn to a smaller section, due to tension, is
called Ductility
58. The unit
of force in S.I. units is Newton
59. The value of
Poisson's ratio always remains Less than one
60. A beam is said
to be of uniform strength, if Bending stress is the same at every section along its longitudinal axis
61. The
coefficient of friction depends upon the Nature of surfaces
62. When loads are
applied proportionately to a frame structure containing its members in one the plane, the structure is called Spaceframe
63. The maximum
bending moment due to a moving load on a simply supported beam occurs Under the load
64. The C.G. of a solid hemisphere lies on the central
radius 3r
65. In
rectangular columns (cross-section b × h), the core is a Rhombus of diagonals b/3 and h/3
66. Dynamic
friction as compared to static friction is Less
67. Forces are
called coplanar when all of them acting on body lie in One plane
68. Ties are load
carrying members of a frame, which are subjected to Axial tension loads
69. A simply
supported beam (l + 2a) with equal overhangs (a) carries a uniformly distributed load over the the whole length, the B.M. changes sign if l > 2a
70. According to
principle of moments If a system of coplanar forces
is in equilibrium, then the algebraic sum of their moments about any point in
their plane is zero
71. Along the the neutral axis of a simply supported beam Fibres do not undergo strain
72. The ratio of
the moment of inertia of a circular plate and that of a square plate for equal
depth is Equal to 3π/16
73. The energy
stored in a beam of length ‘L’ subjected
to a constant B.M. is M2L/2EI
74. Two
non-collinear parallel equal forces acting in opposite direction Constitute a couple
75. If a constant
section beam is subjected to a uniform bending moment throughout, its length
bends to a circular arc
76. As compared
to uniaxial tension or compression, the strain energy stored in bending is only
1/3
77. The effect of
arching a beam is To reduce the bending
moment throughout
78. D'
Alembert's principle is used for Reducing the problem of
kinetics to equivalent statics problem
79. The range
within which a load can be applied on a rectangular column, to avoid any
tensile stress, is One-fifth of the base
80. For the same height,
the bottom width for no tension, For triangular section is same
as that of a rectangular section
81. Coefficient of
friction is the ratio of limiting friction and
normal reaction
82. An arch
may be subjected to thrust, shear force and bending
moment
83. The C.G. of a
right circular solid cone of height h lies at the following distance from the
base h/4
84. For a channel
section, the shear centre lies at a distance of d2b2t/4I
85. For a beam of
uniform strength keeping its depth constant, the width will vary in proportion
to Bending moment (M)
86. The product of
either force of couple with the arm of the couple is called Moment of the couple
87. Simple bending
equation is M/I = E/R = F/Y
88. The algebraic sum of moments of the forces forming a couple about any point in their plane is Equal to the moment of the couple
89. The equivalent length of a column fixed at both ends, is 0.5 l
90. The ratio of
elongations of a conical bar due to its own weight and that of a prismatic bar
of the same length, is 1/3
91. The
possible loading in various members of framed structures are Compression or tension
92. A simply
supported beam of span L carries
a concentrated load W at its
mid-span. The maximum bending moment M is WL/4
93. The weight of
a body is due to the Gravitational force of
attraction towards the centre of the earth
94. The section
modulus of a rectangular section is proportional to the Area of the section
95. The materials
which have the same elastic properties in all directions are called Isotropic
96. A single
force and a couple acting in the same plane upon a rigid body Cannot balance each other
97. Center of
percussion is The point of application
of the resultant of all the forces tending to cause a body to rotate about a
certain axis
98. The shape of
the bending moment diagram over the length of a beam, carrying a uniformly
distributed load is always Parabolic
99. In a
beam, the neutral plane Does not change during
deformation
100. The moment
diagram for a cantilever whose free end is subjected to a bending moment will
be a Rectangle