Stress And Strain

Question 1

What is stress?

Answer 1

When an object is subjected to an external force , it causes deformation and internal forces to bring about a resistance

Question 2

What 5 types of stress are there?

Answer 2

• tensile stress - pulling
• compressive - squeezing
• shear - forces are opposite
• torsion- twist/torque
• bending

Question 3

What is strain?

Answer 3

The change in shape of a body resulting from stress

Question 4

What unit do we use for strain?

Answer 4

None, but remember to put the figure into a percentage by x100

Question 5

What is Hooke’s Law

Answer 5

Up to the elastic limit of the material the extension obtained directly proportional to the load producing it

Question 6

During the tensile test what happens between 0 and A?

Answer 6

• material obeys Hooke’s Law

- material will revert back to original shape

Question 7

What happens between A-B of the tensile test?

Answer 7

• yield area
• plastic deformation will take place
• will not revert back to original shape

Question 8

What happens at point C of the tensile test?

Answer 8

Maximum load the material can withstand

Ultimate tensile strength is calculated

Question 9

What happens at point D of the tensile test

Answer 9

Plastic limit and fracture occurs

Question 10

What is Young modulus of elasticity?

Answer 10

A constant relationship between stress and strain