FOR FERROUS MATERIALS LIKE STEEL, S-N CURVE BECOMES ASYMPTOTIC AT 1...
2.
For ferrous materials like steel, S-N curve becomes asymptotic at 10
6
cycles.
Which of the statements given above is/are correct?
(a) 1 only
(b) 2 only
(c) Both 1 and 2
(d) Neither 1 nor 2
IES 3. Ans. (b) 1 is false: affected
Endurance LimitIES 4. Match List I with List II and select the correct answer using the codes
given below the lists:
[IES-1993]
List I (Material properties)
List II(Tests to determine material properties)
A. Ductility
1. Impact test
B.
Toughness
2.
Fatigue
test
C. Endurance limit
3. Tension test
D. Resistance to penetration
4. Hardness test
Code: A B C D A B C D
(a)
3 2 1 4 (b)
4 2 1 3
(c) 3 1 2 4 (d)
4 1 2 3
IES 4. Ans. (c)
IES 5.
When
σ
and Young's Modulus of Elasticity E remain constant, the energy-
absorbing capacity of part subject to dynamic forces, is a function of its
[IES-1992]
(a) Length
(b) cross-section
(c) volume
(d) none of the above
IES 5. Ans. (c) Strain energy is given by,
⎛
σ
⎞
2
=
⎜
⎟
U A.L.
2E
⎝
⎠
Where
σ
and E remaining constant,
∴U is proportional to (A.L.) which is volume.
Also, since U is a function of
σ
2
, that portion of the part which is prone to high
localised will absorb a high amount of energy, making it vulnerable to failure. Such
a part, therefore, is designed to have such a contour that, when it is subjected to
time-varying or impact loads or others types of dynamic forces, the part absorbs or
less uniform stress distribution along the whole length of the part is ensured.
IES 6.
Fatigue strength of a rod subjected to cyclic axial force is less than that of
a rotating beam of the same dimensions subjected to steady lateral force.
What is the reason?
[IES-2009]
(a) Axial stiffness is less than bending stiffness
(b) Absence of centrifugal effects in the rod
(c) The number of discontinuities vulnerable to fatigue is more in the rod
(d) At a particular time, the rod has only one type of stress whereas the beam has
both tensile and compressive stresses
IES 6. Ans. (d)
Fluctuating Load Consideration for Design
S K Mondal’s
Chapter 5
Soderberg and Goodman DiagramsIES 7.
Assertion (A): Soderberg relation is used for design against fatigue. [IES-1996]
Reason (R): Soderberg relation is based on yield strength of the material whereas
all other failure relations for dynamic loading are based on ultimate strength of the
material.
(a) Both A and R are individually true and R is the correct explanation of A
(b) Both A and R are individually true but R is not the correct explanation of A
(c) A is true but R is false
(d) A is false but R is true
IES 7. Ans. (a)
IES 8.
The design calculations for members subject to fluctuating loads with the
same factor of safety yield the most conservative estimates when using
(a) Gerber relation
(b) Soderberg relation [IES-1995]
(c) Goodman relation
(d) none of the above.
IES 8. Ans. (b)
IES 9. In the figure shown, it
the line AB represents
Goodman criterion of
failure, then soderberg
criterion could be
represented by line
(a) AD
(b) D
(c) DC
(d) AC
[IES-1992]
IES 9. Ans. (d)
Gyroscopic motionIES 10. Consider the following statements:
[IES-2005]