Tensile stress

Tensile stress (also referred to as normal stress or tension) is the stress state leading to expansion; that is, the tensile stress may be increased until the reach of tensile strength, namely the limit state of stress.

The formula for computing the tensile stress in a rod is:

$\sigma ={\frac {F}{A}}$

where $\sigma$ is the tensile stress, $F$ is the tensile force over the rod and $A$ is the cross-sectional area of the rod.

Units for tensile stress are newtons per square meter (N/m², also called pascals, Pa). \sigma is positive for tensile stress while it is negative for compressive stress, regardless of force's direction.

Many of the mechanical properties of a material can be extracted from a tensile test. In a tensile test, a sample is strained at a constant rate and the stress needed to maintain this strain rate is measured. The stress and strain can either be measured in terms of engineering stress and strain or true stress and strain. The elastic modulus, the ultimate tensile stress, the fracture stress, the modulus of toughness, and the modulus of resilience can all be determined from a tensile test.

See also

• Tension
• Tensile strength
• Shear stress
• Strength of materials
• Hooke's law $F=-kx$
• Compression member