When spring index increases, the value of Wahl's stress factor
Increases linearly
Decreases linearly
Remains same
Increases exponentially
Correct Answer :
D. Increases exponentially
Related Questions
Which of the following statement is wrong for a connecting rod?
The connecting rod will be equally strong in buckling about X-axis and Y-axis, if Ixx = 4 Iyy
If Ixx > 4 Iyy, the buckling will occur about Y-axis
If Ixx < 4 Iyy, the buckling will occur about X-axis
The most suitable section for the connecting rod is T-section
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
A screw is said to be over hauling screw, if its efficiency is
More than 50 %
Less than 50 %
Equal to 50 %
None of these
A sliding bearing in which although lubricant is present, the working surfaces __________ contact each other at least part of the time, is called boundary lubricated bearing.
Partially
Fully
Either A or B
None of these
Which is positive drive?
Flat belt drive
V-belt drive
Crossed belt drive
Timing belt
In the calculation of induced shear stress in helical springs, the Wahl's stress factor is used to take care of
Combined effect of transverse shear stress and bending stress in the wire
Combined effect of bending stress and curvature of the wire
Combined effect of transverse shear stress and curvature of wire
Combined effect of torsional shear stress and transverse shear stress in the wire
The material commonly used for machine tool bodies is
Mild steel
Aluminium
Brass
Cast iron
The pitch of threads on a Jock nut in comparison to pitch of nut is
Same
Coarser
Finer
Very fine
In standard taper roller bearings, the angle of taper of outer raceway is
5°
8°
15°
25°
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
The endurance limit of a material with finished surface in comparison to rough surface is
More
Less
Same
More or less depending on quantum of load
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
When compared to the rod of the same diameter and material, a wire rope
Is less flexible
Has a much smaller load carrying capacity
Does not provide much warning before failure
Provides much greater time for remedial action before failure
Gear box is used
To produce torque
For speed reduction
To obtain variable speeds
To increase efficiency of system
The wire ropes make contact at
Bottom of groove of the pulley
Sides and bottom of groove of the pulley
Anywhere in the groove of the pulley
Sides of groove of the pulley
The endurance limit in shear of carbon steel can be obtained by multiplying the endurance limit in flexure by a factor of
0.45
0.55
0.65
0.75
A flange coupling is used to connect two shafts
Which are perfectly aligned
Which are not in exact alignment
Have lateral misalignment
Whose axes intersect at a small angle
The difference between the tooth space and the tooth thickness as measured on the pitch circle, is called
Working depth
Clearance
Backlash
Face width
The material generally used for aircraft components is
Mild steel
High speed steel
Stainless steel
Aluminium
In composite or reverse laid ropes
Direction of twist of wires in strands is opposite to the direction of twist of strands
Direction of twist of wires and strands are same
Wires in two adjacent strands are twisted in opposite direction
Wires are not twisted
When a helical compression spring is cut into halves, the stiffness of the resulting spring will be
Same
Double
One-half
One-fourth
The cracks in helical springs used in railway carriages usually start on the inner side of the coil because of the fact that
It is subjected to a higher cyclic loading than the outer side
It is subjected to a higher stress than the outer side
It is more stretched than the outer side during the manufacturing process
It has a lower curvature than the outer side
According to I.B.R., the efficiency of a triple riveted butt joint with double straps of unequal width (5 rivets per pitch length) should be
45 to 60 %
63 to 70 %
70 to 83 %
80 to 90 %
If the centre distance of the mating gears having involute teeth is increased, then the pressure angle
Increases
Decreases
Remains unchanged
None of these
When bevel gears connect two shafts whose axes intersect at an angle greater than a right angle and one of the bevel gears has a pitch angle of 90°, then they are known as
Crown bevel gears
Angular bevel gears
Mitre gears
Internal bevel gears
A leaf spring in automobiles is used
To apply forces
To measure forces
To absorb shocks
To store strain energy
In designing a flange coupling, the pitch circle diameter of bolts is taken as (where d = Diameter of the shaft)
2d
3d
4d
5d
Oil in journal bearing should be applied at the point where load is
Nil or lightest
Maximum
Average
Any one of the above
The largest diameter of an external or internal screw thread is known as
Minor diameter
Major diameter
Pitch diameter
None of these
The initial tension (in newtons) in a bolt used for making a fluid tight joint like steam engine cover joints, is calculated by the relation (where d = Nominal diameter of bolt in mm)
1420 d
1680 d
2080 d
2840 d