The stress which vary from a minimum value to a maximum value of the same nature (i.e. tensile or compressive) is called
Repeated stress
Yield stress
Fluctuating stress
Alternating stress
Correct Answer :
C. Fluctuating stress
Related Questions
Plastic flow in ductile materials
Increases the seriousness of static loading stress concentration
Lessens the seriousness of static loading stress concentration
Has no effect on it
Depends on other considerations
For a bevel gear having the pitch angle θ, the ratio of formative number of teeth (TE) to actual number of teeth (T) is
1/sinθ
1/cosθ
1/tanθ
sinθ cosθ
The lower deviation is the algebraic difference between the
Actual size and the corresponding basic size
Maximum limit and the basic size
Minimum limit and the basic size
None of the above
Which of the following statement is correct?
The cold rolled shafting is stronger than hot rolled shafting
The hot rolled shafting is stronger than cold rolled shafting
The cold rolled and hot rolled shaftings are equally strong
The shafts are not made by rolling process
If an application calls for stresses on screw threads in one direction only, then the following type of thread would be best suited
Square
Acme
Buttress
BSW
For longitudinal joint in boilers, the type of joint used is
Butt joint with single cover plate
Butt joint with double cover plate
Lap joint with one ring overlapping the other
Any one of the above
The acme threads are usually found on
Spindles of bench vices
Railway carriage couplings
Feed mechanism of machine tools
Screw cutting lathes
A localised compressive stress at the area of contact between two members is known as
Tensile stress
Bending stress
Bearing stress
Shear stress
A type of brake commonly used in motor cars is a
Shoe brake
Band and block brake
Band brake
Internal expanding brake
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 application of third type levers is found in
A pair of tongs
Hand wheel of a punching press
Lever of a loaded safety valve
Handle of a hand pump
For tight leakage joints, following type of thread is best suited
Metric
Buttress
Square
NPT (national pipe threads)
In helical gears, the distance between similar faces of adjacent teeth along a helix on the pitch cylinders normal to the teeth, is called
Normal pitch
Axial pitch
Diametral pitch
Module
The objective of idler pulley in belt drive is to
Decrease the tendency of belt to slip
Increase the power transmission capacity
Increase the wrap angle and belt tension
All the above objectives
The dedendum circle diameter is equal to (where φ = Pressure angle)
Pitch circle diameter × cosφ
Addendum circle diameter × cosφ
Clearance circle diameter × cosφ
Pitch circle diameter × sinφ
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%
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
In a gear, having Involute teeth, the normal to the Involute is a tangent to the
Base circle
Pitch circle
Addendum circle
Dedendum circle
The velocity of sliding ________ the distance of the point of contact from the pitch point.
Is directly proportional to
Is inversely proportional to
Is equal to cos φ multiplied by
Does not depend upon
In levers, leverage is the ratio of
Load lifted to the effort applied
Mechanical advantage to the velocity ratio
Load arm to the effort arm
Effort arm to the load arm
The allowable static stress for steel gears is approximately __________ of the ultimate tensile stress.
One-fourth
One-third
One-half
Double
Which of the following formula is used in designing a connecting rod?
Euler's formula
Rankine's formula
Johnson's straight line formula
Johnson's parabolic formula
The resultant axial load on a bolt depends on
Initial tension
External load applied
Relative elastic yielding (springness) of the bolt and the connected member
All of the above
A metal pipe of 1 m diameter contains a fluid having a pressure of 1 N/mm². If the permissible tensile stress in the metal is 20 N/mm², then the thickness of the metal required for making the pipe will be
5 mm
10 mm
15 mm
25 mm
When the screw in a mechanical screw jack rotates, the load kept on the top of it moves
Axially upwards
Axially downwards
Axially upwards or downwards
None of these
Set screws are
Similar to small size tap bolts except that a greater variety of shapes of heads are available
Slotted for a screw driver and generally used with a nut
Used to prevent relative motion between parts
Similar to stud
The width of the pulley should be __________ width of the belt.
Equal to
Less than
Greater than
None of these
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
If a shaft made from ductile material is subjected to combined bending and twisting moment, calculations based on which one of the following failure theories will give the most conservative value?
Maximum principal stress theory
Maximum shear stress theory
Maximum strain energy theory
Maximum distortion energy theory
A hot short metal is
Brittle when cold
Brittle when hot
Brittle under all conditions
Ductile at high temperature