Engineering Questions with Answers - Multiple Choice Questions
Materials Science MCQ’s – Fatigue
1 - Question
Which of the following is failure of material due to cyclic stress?
a) Brittle fracture
b) Ductile fracture
c) Creep
d) Fatigue
View Answer
Explanation: Fatigue is the type of failure which is observed in that material which is subjected to cyclic stress cycles. It can also be defined as the number of stress cycle a material can withstand before failing.
2 - Question
What can be height of an extrusion or an intrusion which is responsible for crack initiation in case of fatigue (in cm?
a) 2*10-6
b) 2*10-8
c) 10-5
d) 10-8
View Answer
Explanation: In case of fatigue, there is movement of dislocation because of which local deformation called extrusions are form in slip bands which are accompanied by intrusions. These extrusion and intrusion have a height ranging from 10-6 cm to 10-7 cm.
3 - Question
Which of the following is the most common type of failure in industry?
a) Brittle fracture
b) Ductile fracture
c) Creep
d) Fatigue
View Answer
Explanation: Almost 80% of the failure in the engineering industry occur due to fatigue failure. As components are used for a long time, the material is subjected to stress cycles and will fail due to fatigue.
4 - Question
Below which point does fatigue occur?
a) Ultimate strength
b) Fracture point
c) Elastic limit
d) Yield point
View Answer
Explanation: Fatigue is one of the mechanical failures of the metals that occur due to cyclic loading. It occurs when the stress applied is less than the yield stress or yield point.
5 - Question
Which of the following is not a zone of fatigue fracture?
a) Zone of crack nucleation
b) Fatigue zone
c) Elastic zone
d) Final fracture
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Explanation: The elastic zone isn’t a zone of fatigue fracture. The main three zones in order of their occurrence in fatigue fracture are zone of crack nucleation, fatigue zone. Final fracture.
6 - Question
Corrosion can increase fatigue life.
a) True
b) False
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Explanation: The above statement is false. The fatigue life decreases if corrosion, erosion or other chemical attacks are not prevented during processing of the material or during heat treatment.
7 - Question
What is the speed of the motor in rotating beam fatigue test?
a) 200 rpm
b) 500 rpm
c) 1000 rpm
d) 1500 rpm
View Answer
Explanation: In rotating beam fatigue test, the test machine is high speed with the motor running at 1000 rpm. With the help of the motor, the bending moment is applied on the material.
8 - Question
The S-N curve for mild steel never becomes a horizontal line.
a) True
b) False
View Answer
Explanation: The above statement is false. The S-N curve which the curve between stress and number of cycles on the y and x axis respectively becomes a straight line for steel and titanium.
9 - Question
In Wohler’s Fatigue test, how many cycles can cast iron to be subjected to before failure?
a) 10,000,000
b) 100,000,000
c) 5,000,000
d) 1,000,000
View Answer
Explanation: Cast iron or cast steel in Wohler’s Fatigue test can approximately be subjected to 10,000,000 cycles before it fails.
10 - Question
Which of the following is not a theory of fatigue?
a) Orowan theory
b) Griffith’s theory
c) Fatigue limit theory
d) Wood’s theory
View Answer
Explanation: Griffith’s theory is a theory related to fracture mechanics and it isn’t a theory of fatigue. Orowan theory, fatigue limit theory and wood’s theory are the three main theory of fatigue.