Estimation of Fracture Toughness by Testing Notched Fracture Specimens and Applying the Theory of Critical Distances

Table 1

Average apparent fracture toughness obtained for the different materials and notch radii [6, 7].

Material	Notch radius ρ (mm)	𝐾IN (MPam^1/2)	Material	Notch radius ρ (mm)	𝐾IN (MPam^1/2)
PMMA	≈0	2.04	Al7075 (LT)	≈0	27.01
	0.25	2.43		0.15	55.78
	0.32	2.35		0.21	65.73
	0.5	2.71		0.47	83.98
	1.0	4.41		1.0	99.43
	1.5	4.25		2.0	107.58
	2.0	5.38
	2.5	5.36