A plate with an elliptical hole in the centre, with semi-major axis (A) perpendicular to the direction of loading and semi-minor axis (b) along the direction of loading, is subjected to a pull P. The maximum stress induced at the edge of the hole is equal to (where σ = Stress for a plate with no hole i.e. nominal stress)
σ [1 + (b/2a)]
σ [1 + (2a/b)]
σ [1 + (b/3a)]
σ [1 + (3a/b)]
Correct Answer :
B. σ [1 + (2a/b)]
Related Questions
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
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
The temperature at which the new grains are formed in the metal is known as
Lower critical temperature
Upper critical temperature
Recrystallisation temperature
None of these
Two shafts will have equal strength, if
Diameter of both the shafts is same
Angle of twist of both the shafts is same
Material of both the shafts is same
Twisting moment of both the shafts is same
Basic hole is one
Whose upper deviation is zero
Whose lower deviation is zero
Whose lower as well as upper deviations are zero
Does not exist
Screws used for power transmission should have
Very fine threads
High efficiency
Low efficiency
Strong teeth
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
The material generally used for aircraft components is
Mild steel
High speed steel
Stainless steel
Aluminium
If threads on a bolt are left hand, threads on nut will be
Right hand with same pitch
Left hand with same pitch
Could be left or right hand
Right hand with fine pitch
For same pulley diameters, center distance, belt speed and belt and pulley materials,
Open belt drive transmits more power than crossed belt drive
Crossed belt drive transmits more power than open belt drive
Open and crossed belt drives transmit same power
Power transmission does not depend upon open and crossed types of constructions
While designing a screw in a screw jack against buckling failure, the end conditions for the screw are taken as
Both the ends fixed
Both the ends hinged
One end fixed and the other end hinged
One end fixed and the other end free
A tube has the following advantage over pipe
Lighter and easier to handle
Greater shock absorption
Smoother inside walls
All of the above
The contact ratio is the ratio of
Length of arc of recess to the circular pitch
Length of path of contact to the circular pitch
Length of arc of contact to the circular pitch
Length of arc of approach to the circular pitch
In a partial journal bearing, the angle of contact of the bearing with the journal is
120°
180°
270°
360°
A bolt of M 24 × 2 means that
The pitch of the thread is 24 mm and depth is 2 mm
Cross-sectional area of the threads is 24 mm²
The nominal diameter of bolt is 24 mm and pitch is 2 mm
The effective diameter of bolt is 24 mm and there are 2 threads per cm
If T is the actual number of teeth on a helical gear and φ is the helix angle for the teeth, then formative number of teeth is written as
T sec3φ
T sec²φ
T/sec3φ
T cosecφ
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
Tensile strength of a mild steel specimen can be roughly predicted from following hardness test
Brinell
Rockwell
Vickers
None of the above
Basic shaft is one
Whose upper deviation is zero
Whose lower deviation is zero
Whose lower as well as upper deviations are zero
Does not exist
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
Machine 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 two parts
Similar to stud
Cold working
Increases the fatigue strength
Decreases the fatigue strength
Has no influence on fatigue strength
Alone has no influence on fatigue strength
Maximum principal stress theory is applicable for
Ductile materials
Brittle materials
Elastic materials
All of the above
Which of the following property is essential for spring materials?
Stiffness
Ductility
Resilience
Plasticity
Yield point in fatigue loading as compared to static loading is
Same
Higher
Lower
Depends on other factors
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
A spring of stiffness 1000 N/m is stretched initially by 100 mm from the undeformed position. The work required to stretch it by another 100 mm is
5 N-m
7 N-m
10 N-m
15 N-m
The function of cutting oil when threading a pipe is to
Provide cooling action
Lubricate the dies
Help removes chips
All of the above
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
When the length of the journal is equal to the diameter of the journal, then the bearing is said to be a
Short bearing
Long bearing
Medium bearing
Square bearing