Objective 03: Area Expansion of Solids and Holes

Question 1

What is the relationship of the coefficient of area expansion (γ) to the coefficient of linear expansion (α)?

Answer 1

γ = 2α

Question 2

How does the size of a hole in a solid material react to temperature change?

Answer 2

The area of a hole in a piece of a material expands as though the hole itself were made of the same material, regardless of the shape of the hole or the material.

Question 3

What kind of connection between cylinders takes advantage of the behaviour of holes when heated?

Answer 3

Interference/Shrink Fit

Question 4

Interference/Shrink Fit

Answer 4

1. The inside cylinder is made slightly larger than the inside diameter of the outside cylinder
2. The outer cylinder is then heated and the inner cylinder cooled
3. Eventually the inner cylinder fits into the outer cylinder
4. As the inner cylinder expands again upon warming, and the outer cylinder contracts as it cools, a tight fit is formed