Stress concentration factor is defined as the ratio of
Maximum stress to the endurance limit
Nominal stress to the endurance limit
Maximum stress to the nominal stress
Nominal stress to the maximum stress
Correct Answer :
C. Maximum stress to the nominal stress
Related Questions
The maximum stress due to stress concentration in a bar having circular transverse hole, as compared to its static stress without hole will be
Same in both cases
2 times more
3 times more
4 times more
In a marine flange coupling, the pitch circle diameter of bolts is taken as
1.2 d
1.6 d
2d
2.5 d
If a material fails below its yield point, failure would be due to
Straining
Fatigue
Creep
Sudden loading
For a shaft diameter of 200 mm, the number of bolts in a marine flange coupling should be
8
6
4
10
During hot working of metals,
Porosity of the metal is largely eliminated
Grain structure of the metal is refined
Mechanical properties are improved due of refinement of grains
All of the above
The fatigue stress concentration factor is defined as
The ratio of endurance limit with stress concentration to the endurance limit without stress concentration
The ratio of endurance limit without stress concentration to the endurance limit with stress concentration
The product of the endurance limits with and without stress concentration
All of the above
The expression 0.175 - 0.841/T is the Lewis form factor for
14 ½° composite and full depth involute system
20° full depth involute system
20° stub system
None of the above
The stiffness of a closely coiled helical spring subjected to an axial load W is equal to (where G = Modulus of rigidity, and n = Number of active coils)
Gd⁴/ 8D3n
Gd3/ 8D3n
Gd⁴/ 4D3n
Gd⁴/ 8D²n
The material commonly used for machine tool bodies is
Mild steel
Aluminium
Brass
Cast iron
In a belt drive, if the pulley diameter is doubled keeping the tension and belt width constant, then it will be necessary to
Increase the key length
Increase the key depth
Increase the key width
Decrease the key length
A hot short metal is
Brittle when cold
Brittle when hot
Brittle under all conditions
Ductile at high temperature
The elasticity is the property of a material which enables it to
Regains its original shape after deformation when the external forces are removed
Draw into wires by the application of a tensile force
Resists fracture due to high impact loads
Retain deformation produced under load permanently
The property of a bearing material which has the ability to accomodate shaft deflections and bearing inaccuracies by plastic deformation without excessive wear and heating, is known as
Bondability
Embeddability
Comformability
Fatigue strength
In the levers of third type, the mechanical advantage is __________ one.
Less than
Equal to
More than
None of these
In the case of an elastic bar fixed at upper end and loaded by a falling weight at lower end, the shock load produced can be decreased by
Decreasing the cross-section area of bar
Increasing the cross-section area of bar
Remain unaffected with cross-section area
Would depend upon other factors
A screw is said to be over hauling screw, if the
Friction angle is less than helix angle
Friction angle is more than helix angle
Friction angle is equal to helix angle
Efficiency of screw is 100%
The shear stress in a beam varies from zero at the outer fibres to a maximum at the________.
Neutral surface
Upper surface
Lower surface
None of these
A leaf spring in automobiles is used
To apply forces
To measure forces
To absorb shocks
To store strain energy
A tube has the following advantage over pipe
Lighter and easier to handle
Greater shock absorption
Smoother inside walls
All of the above
The spring mostly used in gramophones is
Helical spring
Conical spring
Flat spiral spring
Volute spring
According to I.B.R., when the thickness of boiler shell (t) is greater than 8 mm, then the diameter of rivet hole (d) is obtained by
Equating tearing resistance of the plate to the shearing resistance of the rivets
Equating tearing resistance of the plate to the crushing resistance of the rivets
Equating shearing resistance to the crushing resistance of the rivets
None of the above
The minimum number of teeth on the pinion which will mesh with any gear without interference for 20° full depth involute teeth will be
12
14
18
24
A chain drive transmits __________ power as compared to belt drive.
More
Less
Same
None of these
When a nut is tightened by placing a washer below it, the bolt will be subjected to following type of loads
Compression
Tension
Shear
Combined loads
Auto frettage is the method of
Joining thick cylinders
Calculating stresses in thick cylinders
Pre-stressing thick cylinders
Increasing the life of thick cylinders
A fast and loose pulley drive is used when
Shafts are arranged parallel and rotate in the opposite directions
Shafts are arranged parallel and rotate in the same directions
Shafts are arranged at right angles and rotate in one definite direction
Driven shaft is to be started or stopped whenever desired without interfering with the driving shaft
In order to determine the stresses in a thin cylinder due to an internal pressure, it is assumed that
The effect of curvature of the cylinder wall is neglected
The tensile stresses are uniformly distributed over the section of the walls
The effect of the restraining action of the heads at the end of the pressure vessel is neglected
All of the above
The value of Lewis form factor used in design of gears is
Dependent on number of teeth of a gear
Dependent on system of teeth
Independent of size of teeth
All of these
A tapered key which fits in a key-way in the hub and is flat on the shaft, is known as
Woodruff key
Feather key
Flat saddle key
Gib head key
The ultimate strength of steel in tension in comparison to shear is in the ratio of
1 : 1
2 : 1
3 : 2
2 : 3