Rule of Mixtures Calculator

Rule of Mixtures Formula

Worked Example

Carbon fibre (230 GPa) in epoxy (3.5 GPa) at 60 % fibre volume:

1. Isostrain: E_c = V_fE_f + V_mE_m = 0.6 × 230 + 0.4 × 3.5 = 139.4 GPa
2. Isostress: 1/E_c = V_f/E_f + V_m/E_m → E_c = 8.554729012 GPa

Longitudinal strength V_fσ_f + V_mσ_m′: 2128 MPa · Load carried by the fibres (isostrain): 98.99569584 %

GATE tip

Isostrain gives the upper bound and isostress the lower bound of the composite modulus; real particulate composites lie in between.

More Processing and Materials Calculators

• Rolling Calculator

  Δh_max = μ²R, L = √(RΔh)

  F ≈ σ̄ w L (no friction hill); true strain ln(h₀/h₁)

  Example: Rolling 25 mm plate to 20 mm with 300 mm radius rolls and μ = 0.1: Draft Δh = 5 mm.

  Open the rolling calculator →

• Chvorinov's Rule Calculator

  t = B (V/A)ⁿ

  B mould constant, n ≈ 2; riser modulus ≥ 1.2 × casting modulus

  Example: A 200 × 100 × 50 mm block with B = 2 s/mm² and n = 2: Solidification time t = 6.80272 min.

  Open the chvorinov's rule calculator →

• Polymer Molecular Weight Calculator

  Mₙ = Σ xᵢMᵢ, M_w = Σ xᵢMᵢ² / Σ xᵢMᵢ

  xᵢ number fraction; PDI = M_w/Mₙ ≥ 1; DP = Mₙ/m₀

  Example: Fractions of 10, 20, 30 and 40 kg/mol with number fractions 0.1, 0.3, 0.4 and 0.2: Number-average molecular weight Mₙ = 27000 g/mol.

  Open the polymer molecular weight calculator →

• Radius Ratio Calculator

  r_c / r_a → coordination number

  limits 0.155 (3), 0.225 (4), 0.414 (6), 0.732 (8), 1.0 (12)

  Example: Sodium chloride: Na⁺ 1.02 Å and Cl⁻ 1.81 Å: Radius ratio r_c/r_a = 0.563536.

  Open the radius ratio calculator →

Frequently asked questions

Sources

• The International System of Units (SI), 9th edition (SI Brochure), Bureau International des Poids et Mesures .

Last reviewed: 2026-10-15. Factors are stored exactly and computed with 50-digit decimal arithmetic. See how we verify conversion factors.