Mechanical Properties of Materials (Up to pg31)

Question 1

What is mechanical stress?

Answer 1

The force per unit area (essentially the pressure put upon it)

Question 2

What are the 4 ways in which load can be applied to a material?

Answer 2

Shear, torsion, compression and tension

Question 3

Why do we use Young’s Modulus instead of individual stress and strain graphs?

Answer 3

As it normalises the results by disregarding the geometric dimensions of the associated materials

Question 4

What is mechanical strain?

Answer 4

The ratio of the extension of the material under stress to the original length

Question 5

What are the two main types of strain?

Answer 5

Elastic and plastic, elastic is reversible and plastic is not

Question 6

What is a material’s Young’s Modulus?

Answer 6

The amount by which a material deforms or strains per the unit stress applied to it, otherwise known as stiffness: Stress/strain

Question 7

What is Poisson’s ratio?

Answer 7

The amount by which a material deforms laterally when a vertical load is applied to it. For most metals and many other alloys, their Poisson’s ratio varies between 0.25 and 0.35