Elongation Calculator

Calculate material elongation, strain, and deformation under tension or compression

Calculation Setup

mm
mm
mm

Material Properties (Optional)

Calculation Results

Enter the required values to calculate elongation
Provide at least two values to perform the calculation

Example Calculation

Steel Rod Under Tension

Material: Carbon Steel (fracture strain: 25%)

Original Length (L₀): 100 mm

Final Length (Lf): 105 mm

Calculation Steps

1. Change in length: ΔL = Lf - L₀ = 105 - 100 = 5 mm

2. Elongation: Ep = (ΔL / L₀) × 100%

3. Ep = (5 / 100) × 100% = 5%

4. Result: 5% elongation (within safe limits for steel)

Typical Fracture Strains

Ceramics
0.1 - 0.3% (brittle)
Metals
1 - 60% (ductile)
Polymers
3 - 800% (very ductile)
Composites
1.5 - 3.5% (moderate)

Types of Deformation

ElasticRecoverable
PlasticPermanent
FractureMaterial failure
NeckingLocalized thinning

Quick Tips

Positive elongation = stretching (tension)

Negative elongation = compression

Fracture strain varies greatly by material

Always consider safety factors in design

Temperature affects material ductility

Understanding Elongation

What is Elongation?

Elongation is the measure of how much a material stretches when subjected to tensile (pulling) forces. It's expressed as a percentage of the original length and is a critical property for understanding material behavior under load.

Engineering vs True Strain

This calculator computes engineering strain (Cauchy strain), which uses the original length as reference. True strain considers the instantaneous length during deformation and is more accurate for large deformations.

Material Failure

When elongation exceeds the fracture strain, materials fail catastrophically. Understanding these limits is crucial for safe engineering design and material selection.

Elongation Formula

Basic Formula

Ep = (ΔL/L₀) × 100%

Where ΔL = Lf - L₀

Change in Length:

ΔL = Lf - L₀

Final Length:

Lf = L₀ + ΔL

Original Length:

L₀ = Lf / (1 + Ep/100)

Ep: Elongation percentage (%)

L₀: Original length

Lf: Final length

ΔL: Change in length