Tensile Test

Follows ASTM Standards E 8 and E 8M. (American Society for Testing and Materials)

The specimen:

Here

• Gauge length
• Initial diameter
• Initial area

The setup:

Test will be done until the specimen fractures. Results are converted to engineering stress and strain, and plotted.

Load cell

Measures the force applied to the specimen.

Extensometer

Used to measures the elongation (increase in length) in the specimen.

Tensile tests for brittle material

The σ-ε behavior of brittle materials cannot be assessed by a tensile test because:

• Difficult to prepare test specimens
• Difficult to grip brittle materials without fracturing them

For brittle materials

Fracture strength is normally specified for engineering design purposes. Tensile strength is calculated from its modulus of rupture (MOR) or flexural strength value.

Necking

All deformation up to the maximum point is uniform throughout the specimen.

At this maximum stress, a neck begins to form – known as necking. All subsequent deformation is confined to this neck.

Fracture

Fracture occurs at the neck.