Deformation of Solids

Hooke’s Law

For an elastic material the extension is directly proportional to the load up to the maximum load known as the limit of proportionality.

Elastic

Material which returns to its original size and shape after the load is removed.

Plastic

A material stretched beyond its elastic limit which is permanently deformed and usually characterised by large extensions for small increases in loads.

Elastic Limit

The load point beyond which the material no longer returns to its original length.

Stress

The applied force per unit area of cross-section.

Strain

The ratio of the extension to its original length.

Young Modulus

The ratio of stress to strain (within the limits of proportionality).