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

Table 2

Fracture toughness (𝐾_IC) estimations obtained by using the proposed methodology.

Material	Notch radii	ρ in (13)	𝐾IN in (13)	L (mm)	Measured 𝐾IC	Estimated 𝐾IC	Deviation from
	combination	(mm)	(MPam^1/2)		(MPam^1/2)	(MPam^1/2)	measured 𝐾IC (%)
PMMA	0.25–0.32	0.25	2.43	—	2.04	—	—
	0.25–0.50			0.19		2.48	21.5
	0.25–1.0			0.014		1.08	−47.0
	0.25–1.5			0.115		2.29	12.2
	0.25–2.0			0.046		1.76	−13.7
	0.25–2.5			0.086		2.14	4.9
Al7075-T651 (LT)	0.15–0.21	0.15	55.78	0.010	27.01	26.89	0.44
	0.15–0.47			0.060		51.11	89.2
	0.15–1.0			0.094		55.90	106.9
	0.15–2.0			0.132		58.46	116.4