The ratio of endurance limit in shear to the endurance limit in flexure is
0.33
0.4
0.5
0.55
Correct Answer :
D. 0.55
Related Questions
In V-belt drive, belt touches
At bottom
At sides only
Both at bottom and sides
Could touch anywhere
Two shafts of the same length and material are joined in series. If the ratio of their diameters is 2, then the ratio of their angles of twist will be
2
4
8
16
When two springs are in series (having stiffness K), the equivalent stiffness will be
K
K/2
2K
K/4
Which of the following key is preferred for the condition when a large amount of impact type torque is to be transmitted in both direction of rotation?
Woodruff key
Feather key
Gib-head key
Tangent key
Elastic nut is a locking device in which
One small nut is tightened over main nut and main nut tightened against smaller one by loosening, creating friction jamming
A slot is cut partly in middle of nut and then slot reduced by tightening a screw
Hard fibre or nylon cotter is recessed in the nut and becomes threaded as the nut is stewed on the bolt causing a tight grip
Through slots are made at top and a cotter pin is passed through these and a hole in the bolt, and cotter pin splitted and bent in reverse direction at other end
The arms of the pulleys for flat belt drive have
Elliptical cross-section
Major axis in plane of rotation
Major axis twice the minor axis
All the three characteristics
Two helical springs of the same material and of equal circular crosssection, length and number of turns, but having radii 80 mm and 40 mm, kept concentrically (smaller radius spring within the larger radius spring), are compressed between two parallel planes with a load W. The inner spring will carry a load equal to
W/2
2W/3
W/9
8W/9
The toughness of a material _________ when it is heated
Does not change
Increases
Decreases
None of the Above
When the shaft rotates in anticlockwise direction at slow speed in a bearing, it will
Have contact at the bottom most of the bearing
Move towards right of the bearing making no metal to metal contact
Move towards right of the bearing making the metal to metal contact
Move towards left of the bearing making metal to metal contact
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
The plasticity is the property of a material which enables it to
Regain its original shape after deformation when the external forces are removed
Draw into wires by the application of a tensile force
Resist fracture due to high impact loads
Retain deformation produced under load permanently
For maximum power, the velocity of the belt will be
√(T/m)
√(T/2m)
√(T/3m)
None of these
The helix angle for single helical gears ranges from
10° to 15°
15° to 20°
20° to 35°
35° to 50°
The number of slots in a 25 mm castle nut is
8
4
2
6
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
The stress in the threaded part of the bolt will be __________ as compared to the shank.
Same
Higher
Lower
None of these
In cylindrical cams, the follower moves
In a direction perpendicular to the cam axis
In a direction parallel to the cam axis
In any direction irrespective of cam axis
Along the cam axis
Which of the following statement is wrong?
The pitch of rivets is obtained by equating the tearing resistance of the plate to the shearing resistance of the rivets
The pitch of rivets should not be less than 2d, where d is the diameter of rivet hole
The maximum value of the pitch of rivets for a longitudinal joint of a boiler, as per I.B.R., is given by Pmax = C.t + 41.28 mm
According to I.B.R., the thickness of butt strap shall not be less than 5 mm
For steel, the ultimate strength in shear as compared to ultimate strength in tension is
1/2
1/3
1/4
2/3
According to maximum shear stress theory, the maximum shear stress in the shaft is
(1/2) × √(σ² + 4τ²)
√(σ² + 4τ²)
(1/2) × [σ + √(σ² + 4τ²)]
σ + √(σ² + 4τ²)
In most machine members, the damping capacity of the material should be
Low
Zero
High
Could be anything
18/8 steel contains
18% nickel and 8% chromium
18% chromium and 8% nickel
18% nickel and 8% vanadium
18% vanadium and 8% nickel
Whether any core is required in wire ropes
Yes
No
Sometimes
Rarely
A column is known as a long column if the slenderness ratio is
40
50
70
100
The notch angle of the Izod impact test specimen is
10°
20°
30°
45°
Screws used for power transmission should have
Very fine threads
High efficiency
Low efficiency
Strong teeth
When the bolt is very yielding as compared to the connected members, then the resultant load on the bolt will be equal to the
Initial tension
External load applied
Sum of the initial tension and external load applied
Initial tension or external load, whichever is greater
The radial distance of a tooth from the pitch circle to the top of the tooth is called
Addendum
Dedendum
Clearance
Working depth
Endurance limit or fatigue limit is the maximum stress that a member can withstand for an infinite number of load applications without failure when subjected to
Dynamic loading
Static loading
Combined static and dynamic loading
Completely reversed loading
A V-belt designated as B 4430 LP has
4430 mm as diameter of small pulley
4430 mm as nominal pitch length
4430 mm as diameter of large pulley
4430 mm as centre distance between pulleys