Influence of Root Rotation on Delamination Fracture Toughness of Composites

Table 3

Critical load and corresponding displacement for the measured crack length of a DCB specimen made of unidirectional carbon/PEEK composite.

Test results			Present analysis
Crack length,; (mm)	(N)	(mm)	(N); (10)	(mm); (8)	% relative error in		(13),
					Load	Displacement
51	120.59	10.95	119.48	11.45	0.92	−4.55	119.48
52	119.14	11.07	117.18	11.91	1.65	−7.57	117.18
53	117.01	11.89	114.97	12.37	1.74	−4.02	114.97
54	115.06	12.72	112.84	12.84	1.93	−0.94	112.84
55	112.79	13.16	110.79	13.32	1.78	−1.22	110.79
60	104.44	14.77	101.56	15.85	2.76	−7.32	101.56
65	96.56	17.98	93.74	18.60	2.91	−3.46	93.74
70	89.80	20.00	87.05	21.58	3.06	−7.90	87.05
75	84.91	23.61	81.24	24.77	4.32	−4.91	81.24
80	76.98	26.72	76.17	28.18	1.05	−5.45	76.17

Lay-up: 0₂₆,  mm,  mm,  mm,  GPa, , and  J/m².