Strength of material interview questions / Strength of Material Interview Question and Answers

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