Related Rule Study of Subcritical Crack Growth and Threshold Values in Transversely Isotropic Slates

Table 5

Fracture toughness testing value (MN·m^-3/2).

β	Specimen no.		Average
0°	0-1	4.14	4.21
	0-2	4.25
	0-3	4.24
30°	1-1	3.15	3.02
	1-2	3.00
	1-3	2.91
45°	2-1	2.60	2.65
	2-2	2.72
	2-3	2.63
70°	3-1	2.92	2.79
	3-3	2.66
80°	4-1	2.55	2.81
	4-2	3.00
	4-3	2.88
90°	5-1	3.15	2.95
	5-2	2.90
	5-3	2.80