Influence of Root Rotation on Delamination Fracture Toughness of Composites

Table 2

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

Test results			Present analysis
Crack length, (mm)	(N)	(mm)	(N); (10)	(mm); (8)	% relative error in		(13),
					Load	Displacement
51	41.92	5.15	41.55	4.86	0.88	5.53	43.14
52	40.90	5.31	40.78	5.05	0.30	4.95	42.31
53	39.74	5.48	40.04	5.24	−0.75	4.40	41.51
54	39.09	5.65	39.32	5.43	−0.58	3.87	40.74
55	38.71	5.82	38.63	5.63	0.20	3.37	40.00
60	35.55	6.57	35.51	6.66	0.10	−1.34	36.67
65	31.97	7.74	32.86	7.78	−2.77	−0.57	33.85
70	30.97	8.82	30.57	8.99	1.27	−1.99	31.43
75	27.44	9.97	28.59	10.29	−4.19	−3.15	29.33
80	26.46	11.21	26.84	11.67	−1.45	−4.10	27.50

Lay-up: 0₂₄,  mm,  mm,  mm,  GPa,  Nm, and  J/m².