What is Fiber Mass Fraction (Wf)?

Fiber mass fraction (Wf) expresses the percentage of fiber weight in a composite material. It is widely used in raw material proportioning, production weighing, burn-off tests, and quality control for carbon, glass, aramid or natural fiber composites.

Calculation Formula (Rule of Mixtures – Volume to Weight)

Wf = (ρf × Vf) / (ρf × Vf + ρm × (1 − Vf)) × 100%

Where:
• Vf = fiber volume fraction (0–1)
• ρf = fiber density (g/cm³)
• ρm = matrix density (g/cm³)

Enter Values

Fiber Volume Fraction Vf (0–1) Fiber Density ρf (g/cm³) Matrix Density ρm (g/cm³)

Wf = ?

Typical Real-World Example

Carbon fiber prepreg: Vf = 0.58, ρf = 1.79 g/cm³, epoxy ρm = 1.25 g/cm³ → Wf ≈ 0.665 (66.5%). This is a standard value for high-performance aerospace and automotive composites.

Applications in Engineering

Raw material weighing and mixing in production
Burn-off test validation and quality inspection
Material cost calculation and batch preparation
Conversion between design and manufacturing parameters

← Back to All Calculators