**Tensile Properties:-** Tensile is related to tension of fibers.Fibers usually experience tensile loads whether they are used for apparel or technical structures.

Following are the main tensile properties of textiles fibers:-

- Tenacity
- Breaking extension
- Work of rupture
- Initial modulus
- Work factor
- Work recovery
- Elastic recovery
- Yield stress
- Yield strain
- Yield point
- Breaking load
- Creep

**Description of each is given below:**

**1. Tenacity: **

The ratio of load required to break the specimen and the linear density of that specimen is called tenacity. Mathematically, Tenacity = Load required to break the specimen / Linear density of the specimen Unit: gm/denier, gm/Tex, N/Tex, CN/Tex etc.

**2. Breaking extension: **

The elongation necessary to break a textile material is a useful quantity. It may be expressed by the actual percentage increase in length and is termed as breaking extension. Mathematically, Breaking extension (%) = (Elongation at break / Initial length) × 100%

**3. Work of rupture: **

Work of rupture is defined as the energy required to break a material or total work done to break that material. Unit: Joule (J)

**4. Initial modulus: **

The tangent of angle between the initial curve and the horizontal axis is equal to the ratio of stress and strain.

In engineering science, the ratio is termed as Young’s Modulus and in textile we use the terms as Initial Young’s Modulus.

Initial modulus, tan α = stress / strain Tan α ↑↓ → extension ↓↑

**5. Work factor: **

The ratio between work of rupture and the product of breaking load and breaking elongation is called work factor. Work factor = work of rupture / (breaking load × breaking elongation)

**6. Work recovery: **

The ratio between work returned during recovery and total work done in total extension is called work recovery.

Total extension = Elastic extension + Plastic extension

Total work = work required to elastic extension + work required to plastic extension.

**7. Elastic recovery: **

The power of recovery from a given extension is called elastic recovery. Elastic recovery depends on types of extension, fiber structure, types of molecular bonding and crystalline of fiber. The power of recovery from a given extension is called elastic recovery. Elastic recovery depends on types of extension, fiber structure, types of molecular bonding and crystalline of fiber.

**8. Yield point. **

The point up to which a fiber behaves elastic deformation and after which a fiber shows plastic deformation is called yield point.

**9. Yield stress **

The stress at yield point is called yield stress.

**10. Yield strains: **

The strain at yield point is called yield strain.

**11. Breaking load: **

The load which is required to break a specimen is called breaking load.

**12. Creep: **

When a load is applied on the textile material an instantaneous strain is occurred, but after that the strain will be lower with the passing time. This behavior of the material is termed as creep.

__There are two types of creep:__

Temporary creep

Permanent creep

Here,

AB = initial length of the specimen

AD = final length after recovery

BD = total extension

CD = elastic extension

BC = plastic extension

Total extension = Elastic extension + Plastic extension

So, Elastic recovery (%) = (Elastic extension/total extension) ×100% = (CD/BD) × 100%

So, Plastic recovery = (plastic extension/total extension) ×100% = (BC/BD) ×100%