Table 2.

Shear strength ${\tau }_1$ and compressive strength ${\sigma }_1$ of friction materials and their ratios.

	Basalt Fiber (wt.%)	Shear Strength ${\mathit{\tau }}_1$ (MPa)	Compressive Strength ${\mathit{\sigma }}_1$ (MPa)	$\frac{{\mathit{\tau }}_1}{{\mathit{\sigma }}_1}$	$\frac{{\mathit{\tau }}_1}{{\mathit{\sigma }}_1}-\frac{{\mathit{\tau }}_2}{{\mathit{\sigma }}_1}$	$\mathit{\mu }$
S01	10	13.3	56.2	0.2367	0.2324	0.404
S04	12	14.8	59.2	0.2500	0.2460	0.419
S05	14	17.1	63.3	0.2701	0.2664	0.436
S06	16	20.9	74.6	0.2802	0.2770	0.451