Machine Design 1 (Terms OT) Flashcards
Poisson’s ratio for steel varies
0.25-0.33
The ratio of the load on a spring to its corresponding axial deflection.
spring scale
The irregularity in the stress distribution caused by abrupt changes of form
stress raiser
Based on ASME Code, the strength of a shaft with a keyway is almost reduced to as much as
75%
A square-threaded jack has a lead angle of λ. The jack will not be self-locking when the coefficient of friction (f) is
f<tan λ
Slenderness ratio is the ratio of
effective length of column to least radius of gyration of the column
Transmission shaft driven by the prime mover.
line shaft
The ratio of the ultimate stress or yield stress of a material to the design stress is known as
factor of safety
The stress concentration factor when a machine member with stress raiser is subjected to compression is approximately
1.0
A stress which varies from a minimum value to a maximum value of the same nature (ie. tensile or compressive) is called
varying stress
When helical compression spring is cut into three, the stiffness of the resulting spring will be
three times
Hooke’s law holds good up to
elastic limit
The modulus of elasticity for shear for mild steel is approximately equal to
80 GPa
The ratio of linear stress to linear strain within the proportional limit is called
Modulus of elasticity
The Young’s modulus for mild steel is approximately equal to
210 GPa
It is the stress at which the stress-strain curve begins to deviate from the straight line.
elastic limit
When a hole of diameter ‘d’ is punched in a metal of thickness ‘t’, then the force required to punch a hole is equal to
πdtSu
In torsion, the minimum stress happens at
the centroidal axis
Two shafts A and B are made of the same material. The diameter of the shaft A is thrice as that of shaft B. The power transmitted by the shaft A will ……. of shaft B.
twenty seven times
In the stress analysis of thin-walled cylindrical pressure vessels, the hoop stress is ……. of the longitudinal stress
twice
It is a standard thread which has an included angle of 60°.
Metric thread
What is the approximate solid height for a compression helical spring with ground ends?
NcDw
A type of end fixity where the end of the column is guided so that it cannot sway from side to side, but offers no resistance to rotation of the end.
pinned-end
For a rectangular cross-section with width ‘b’ and height ‘h’ and ‘h’>’b’, the lesser radius of gyration is
0.289b
Which of the following thread is not used for power transmission in either direction?
Buttress thread
Maximum Shear Stress theory is generally used for
ductile materials
A load that varies from a certain minimum to a certain maximum having different magnitudes between limits and with different directions of application.
fluctuating load
When a machine member is subjected to the action of two equal and opposite couples acting in parallel planes, then the machine member is said to be subjected to
none of the above
Failure of a material is called fatigue when it fails
below the yield point
