## What is true strain

same as above equation for true stress, P / A

True strain is given by:

True stress and strain are often not required. When the yield strength is exceeded, the material deforms. The component has failed because it no longer has the original intended shape. Furthermore, a significant difference develops between the two curves only when necking begins. But when necking begins, the component is grossly deformed and no longer satisfies its intended use.

What is true strain same as above equation for true stress, P / A True strain is given by: True stress and strain are often not required. When the yield strength is exceeded, the material

## True Stress & True Strain | Engineering Stress – 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 Strain

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

### 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:

where K is called the strength coefficient and n the Strain Hardening exponent.

### Relation between True and Engineering Stress-Strain

For a given value of the load and elongation, the true stress is higher than the Engg. stress, while the true strain is smaller than the Engg. Strain. The relationship between the true and engineering values is given by the formula:

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. The true strain (e) is defined as the instantaneous elongation per unit length of the specimen. The relationship between true stress and true strain i.e. the flow curve can be expressed using the power law: