This set of Mechanical Behaviour Multiple Choice Questions & Answers (MCQs) focuses on “Notch-Bar Impact Test”.
1. Kinetic energy of Izod hammer is given as _________
Explanation: Kinetic energy is equal to wh. It is the maximum energy that the hammer has just before hitting the specimen. w is the weight of hammer and h is height.
2. Work of fracture is given by __________
Explanation: Work of fracture is the energy absorbed by the sample just before fracture. It is wh-wh’. Here h’ is height rise of centre of gravity of hammer.
3. Standard specimen has v-notch of ___________ depth.
Explanation: Standard specimen is used for Charpy test. It has a V notch in the middle. It is of depth 2mm.
4. What position is used for placing specimen in anvil for Izod test?
a) Supported vertical
b) Freely vertical
c) Supported horizontally
d) Freely horizontally
Explanation: The specimen is supported in Izod test. It is kept vertical in this case. Notch is facing the striking hammer.
5. What is the cross section of a standard specimen for impact testing?
Explanation: Standard specimen cross section may be round or square. When it is square, it is kept 10mm×10mm. V-notch may be in middle.
6. In _________ test, there are two kinds of notches.
Explanation: Tensile test doesn’t involve notches. In the Izod test, there is only one type of notch. In Charpy, there are two type notches of V and U type.
7. Izod uses _________ hammer as striker and Charpy use _________ hammer.
a) Farming, farming
b) Farming, Ball pin
c) Ball pin, forming
d) Ball pin, ball pin
Explanation: Different hammers are used as striker in both test. Izod uses forming hammer. Charpy uses ball pin hammer.
8. What are specimen dimensions for a Charpy test?
Explanation: Charpy specimen’s dimensions are 55×10×10mm. Izod specimen dimensions are 75×10×10mm. Notch is placed at the middle in Charpy test.
9. Which impact test would you use for duralumin?
a) Charpy (U notch)
c) Charpy (V notch)
d) No need
Explanation: Duralumin is FCC structure material. It doesn’t undergo ductile-brittle transition. So impact test is not performed.
10. Dynamic tests are generally applied to _______
a) Austenitic stainless steel
c) Single phase brass
d) Tool steels
Explanation: Dynamic tests are generally applied to tool steels. Because these are BCC structure, and undergo transition. Austenitic steels, duralumin and brass are of FCC structure.
11. Izod impact test is preferred for plastics.
Explanation: Plastics are tested via Izod test. Charpy has its advantages for metallic materials.
12. In a Charpy test, compressive stresses form around the notch.
Explanation: In the Izod test, compressive stresses form around the notch. While specimen is kept free in Charpy. So no generation of such stresses takes place.
Sanfoundry Global Education & Learning Series – Mechanical Behaviour & Testing of Materials.
To practice all areas of Mechanical Behaviour & Testing of Materials, here is complete set of 1000+ Multiple Choice Questions and Answers.