An attempt to unify the Brinell, Janka and Monnin hardness of wood on the basis of Meyer law

Journal of Wood Science

Official Journal of the Japan Wood Research Society

Table 5 Results of measurements of mean hardness values for sample D of beech wood

Beech 672 kg/m³ Sample D (h 9%)	Hardness measures (mean value ± standard error) (MPa)
Beech 672 kg/m³ Sample D (h 9%)	Spherical (ball)		Cylindrical
Indenter diameter D (mm)	New measure H_Kb	Brinell H_B	New measure H_Kc	Brinell type H_Bc
10	31.19 ± 0.70	31.37 ± 0.74	30.99 ± 0.85	31.27 ± 2.03
15	29.07 ± 0.55	29.22 ± 0.49	35.20 ± 0.65	37.03 ± 0.93
30	28.41 ± 0.49	27.01 ± 0.83	31.74 ± 0.56	30.49 ± 0.99
Arithmetic mean	29.6 ± 1.5*	29.2 ± 2.2*	32.6 ± 2.2*	32.9 ± 3.6*
Average means	31.1 ± 2.0*

*Standard deviation of the type s_m−1 for m = 3 or m = 4 without the t-Student factor, but also without divisor \(\sqrt m\) for the standard error of the mean value