32 Questions
What is the purpose of the impact test?
To measure the energy absorbed in breaking the specimen
What do the Charpy and Izod tests measure?
Impact energy or impact toughness
What shape is the specimen for both Charpy and Izod tests?
Bar of square cross-section with a V-notch
Under what conditions can impact test conditions be chosen?
Deformation at a relatively low temperature, high strain rate, and triaxial stress state
What does the energy value from an impact test indicate?
Toughness of the material under test
What does the V-notch in the specimen for Charpy and Izod tests help to measure?
Impact energy or impact toughness
Which impact test uses a weighted pendulum hammer to apply an impact blow at a fixed height?
Charpy V-notch (CVN) technique
What is the primary difference between the Charpy and Izod techniques?
The manner of specimen support
What is the measure of impact energy calculated from the difference between h and h̀?
Energy absorption
What is the ductile-to-brittle transition temperature (DBTT)?
The temperature at which a material behaves in a brittle manner in an impact test
At what temperature does the impact energy drop suddenly over a relatively narrow range?
At very low temperatures
What is indicated by the appearance of a dull and fibrous fracture surface?
Ductile fracture
What does the Charpy V-notch (CVN) technique measure?
Energy absorption
What factor does the ductile-to-brittle transition temperature (DBTT) depend on?
Strain rate
What is the mode of fracture at higher temperatures according to the text?
Ductile
What is used to strike and fracture the specimen at the notch in the Charpy V-notch (CVN) technique?
Knife edge mounted on the pendulum
The primary difference between the Charpy and Izod techniques lies in the manner of specimen support.
True
The energy absorption computed from the impact-testing apparatus is a measure of the impact toughness.
True
One of the important uses of the impact test is to determine whether a material experiences a ductile-to-brittle transition with decreasing temperature.
True
The ductile-to-brittle transition temperature (DBTT) depends only on the strain rate.
False
The temperature of the specimen has no influence on the test result and the fracture mode.
False
As the temperature is lowered, the impact energy increases steadily.
False
The appearance of fracture surface is not an indication for the nature of fracture and is not used in transition temperature determination.
False
For ductile fracture, the surface appears shiny and smooth.
False
The Charpy V-notch (CVN) technique measures impact strength in Joules per meter square.
False
Izod technique uses a weighted pendulum hammer to apply an impact blow at a fixed height.
False
The impact test involves striking a standard specimen with a pendulum and measuring the energy absorbed in breaking the specimen.
True
The impact energy value indicates the ductility of the material under test.
False
Charpy and Izod are the names of two standardized tests used to measure impact energy or impact toughness.
True
The specimen for both Charpy and Izod tests is in the shape of a bar with a circular cross-section.
False
Deformation at a relatively high temperature is one of the standardized test conditions for representing severe potential for fracture in an impact test.
False
The Izod test uses a V-notch with 90° depth machined into the specimen.
False
Test your knowledge of impact toughness and design against impact in mechanical engineering with this quiz. Topics include impact test, ductile-to-brittle transition, and design against impact. Prepared by Dr. Reham Reda Abbas.
Make Your Own Quizzes and Flashcards
Convert your notes into interactive study material.
Get started for free
