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Wood Hardness

Reference data and engineering information about wood hardness for material properties applications.

woodhardness

Overview

Engineering reference data for Wood Hardness in material science and properties.

Key Formulas

Stress

σ=FA\sigma = \frac{F}{A}

Force per unit area.

Strain

ε=ΔLL0\varepsilon = \frac{\Delta L}{L_0}

Change in length per original length.

Hooke's Law

σ=Eε\sigma = E \varepsilon

Stress proportional to strain in elastic region.

Thermal Expansion

ΔL=αL0ΔT\Delta L = \alpha L_0 \Delta T

Length change due to temperature.

Variables

Symbol Description Unit
σ\sigma Stress Pa
ε\varepsilon Strain —
EE Young's modulus Pa
α\alpha Thermal expansion coefficient 1/°C
ΔT\Delta T Temperature change °C

Test Procedure

The Janka hardness test measures the resistance of wood to denting and wear. It determines the force required to embed an 11.28 mm (0.444 in) diameter steel ball to half its diameter (5.64 mm) into the wood sample.

Formulas

The key conversion between units used in hardness measurement is: 1 N=0.2248 lbf1 \, \text{N} = 0.2248 \, \text{lbf}

The force (FF) applied during the Janka test is directly measured. The test result is reported as: Janka Hardness=F\text{Janka Hardness} = F

Wood Hardness Data

The following table provides the Janka Hardness values and assigned grades for common wood species.

Interactive Charts

References