Engineering Stress and Strain - Curve

Engineering Stress These quantities are defined relative to the original area and length of the specimen. The engineering stress (øe) at any point is defined as the ratio of the instantaneous load or force (F) and the original area (Ao). Engineering Stress Engineering Strain

Engineering Strain:

The engine

True Stress and Strain Also see Engineering Stress and Strain True Stress The true stress (ø) uses the instantaneous or actual area of the specimen at any given point, as opposed to the original area used in the engineering values. TRUE STRESS FORMULA

True Strain

The true strain (e) is defined as the instantaneous elongation per unit length of the specimen.

TRUE STRAIN

Relation between True Stress and True Strain

The relationship between true stress and true strain i.e. the flow curve can be expressed using the power law:

TRUE STRESS & TRUE STRAIN RELATIONSHIP

where K is called the strength coefficient and n the Strain Hardening exponent.ering strain (e) is defined as the ratio of the change in length (L-Lo) and the original length (Lo).

Engineering Strain.

Engineering Stress And Strain Curve:

Engineering stress-strain curve is obtained from the load-elongation curve. The Yield point, called the yield strength signifies the start of the plastic region.