The resistance to fatigue of a material is measured by
Elastic limit
Ultimate tensile strength
Young's modulus
Endurance limit
Correct Answer :
D. Endurance limit
Related Questions
The contact ratio for gears is
Zero
Less than one
Greater than one
None of these
The deflection of a cantilever beam under load W is 8. If its width is halved, then the deflection under load W will be
2/8
8/2
4/8
8/4
Factor of safety for fatigue loading is the ratio of
Elastic limit to the working stress
Elastic limit to the yield point
Endurance limit to the working stress
Young's modulus to the ultimate tensile strength
Silver based solder is used for
Flaring
Brazing
Soft soldering
Fusion welding
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
The connecting rod bolts are tightened up so that tightening stress
Is just sufficient to hold parts together
Approaches yield point
Is 50% of yield point
Is about yield point divided by safety factor
A stud
Has a head on one end and a nut fitted to the other
Has head at one end and other end fits into a tapped hole in the other part to be joined
Has both the ends threaded
Has pointed threads
The fatigue life of a part can be improved by
Electroplating
Polishing
Coating
Shot peening
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
According to Indian standards, the diameter of rivet hole is made larger than the basic size of rivet by
0.5 mm upto rivet diameter of 24 mm
1 mm for rivet diameter from 27 mm to 36 mm
2 mm for rivet diameter from 39 mm to 48 mm
All of the above
When a closely coiled helical spring is subjected to a couple about its axis, the stress induced in the wire material of the spring is
Bending stress only
A combination of torsional shear stress and bending
Direct shear stress only
A combination of bending stress and direct shear stress
The angle of twist of shaft is
Directly proportional to (shaft diameter)²
Inversely proportional to (shaft diameter)²
Directly proportional to (shaft diameter)⁴
Inversely proportional to (shaft diameter)⁴
A sliding bearing which can support steady loads without any relative motion between the journal and the bearing, is called
Hydrostatic lubricated bearing
Hydrodynamic lubricated bearing
Boundary lubricated bearing
Zero film bearing
In leaf springs, the longest leaf is known as
Master leaf
Lower leaf
Upper leaf
None of these
According to Indian standards, a bolt thread of 6 mm size of coarse pitch and with allowance on the threads and normal tolerance grade is designated as
M6
M8
M6 - 8d
M8 - 6d
When an open coiled helical compression spring is subjected to an axial load (W), the compression produced in the spring will be (where n = No. of active turns of the spring, and G = Modulus of rigidity for the spring material)
2WD3n/Gd⁴
4WD3n/Gd⁴
8WD3n/Gd⁴
16WD3n/Gd⁴
When a close coiled helical spring is compressed, its wire is subjected to
Tension
Shear
Compression
All of the above
Two rigid plates are clamped by means of bolt and nut with an initial force F. After tightening, a separating force P (P < F) is applied to the lower plate, which in turn acts on the nut. The tension in the both after this is
F + P
F P
P
F
If a load W is applied instantaneously on a bar; Then the stress induced in bar will
Be independent of ratio of mass of load W to mass of bar (y)
Increase with increase in y
Decrease with decrease in y
Depend on other considerations
The toughness of a material _________ when it is heated
Does not change
Increases
Decreases
None of the Above
At low temperatures (say 75°C) the notched bar impact value of steel
Increases markedly
Decreases markedly
Remain same
Depends on heat treatment carried out
In designing thick cylinders, the equation used is
Lame's equation
Birnie's equation
Clavarinos' equation
All of these
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
In a multiple V-belt drive, if one of the belts break, then
Only the broken belt is replaced
The entire set of belts is replaced
The broken belt and the belt on either side of it, is replaced
The broken belt need not to be replaced
Two shafts A and B are made of the same material. The diameter of shaft A is twice as that of shaft B. The power transmitted by the shaft A will be __________ of shaft B.
Twice
Four times
Eight times
Sixteen times
In order to have a connecting rod equally strong in buckling about X-axis and Y-axis, the moment of inertia about X-axis should be __________ the moment of inertia about Y-axis.
Equal to
Twice
Three times
Four times
A spring is used to
Measure forces
Apply forces
Store energy
All 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
In hydrostatic bearings
The Oil film pressure is generated only by the rotation of the journal
The oil film is maintained by supplying oil under pressure
Do not require external supply of lubricant
Grease is used for lubrication
The notch sensitivity q is expressed in terms of fatigue stress concentration factor Kf and theoretical stress concentration factor Kt as
(Kf + 1)/ (Kt + 1)
(Kf - 1)/ (Kt - 1)
(Kt + 1)/ (Kf + 1)
(Kt - 1)/ (Kf - 1)