Fracture Energy Estimation of DCB Specimens Made of Glass/Epoxy: An Experimental Study

Table 3

Critical load, 𝑃_cr, and corresponding displacement, δ _cr, for the measured crack length of a DCB specimen made of cross-ply glass/epoxy composite.

Test results			Present analysis
Crack length, 𝑎 (mm)	𝑃 (N)	δ (mm)	𝑃cr (N) (12)	δ cr (mm) (8)	% Relative error in		𝑃max, (18)
					Load	Displacement
48	72.27	6.46	74.11	8.13	−2.54	−25.97	77.32
49	72.11	7.03	72.66	8.46	−0.75	−20.45	75.74
50	71.89	7.58	71.26	8.80	0.88	−16.08	74.23
51	69.89	8.23	69.92	9.14	−0.03	−11.10	72.77
52	68.55	8.65	68.62	9.49	−0.11	−9.76	71.37
57	65.90	10.57	62.81	11.33	4.68	−7.24	65.11
62	61.93	16.47	57.91	13.34	6.49	19.03	59.86
67	59.38	18.29	53.71	15.50	9.54	15.24	55.39
72	51.65	19.89	50.09	17.83	3.03	10.35	51.55

Layup: [0/90]₃, 𝐵=25 mm, 2ℎ=6.16 mm, 𝑎_𝑜=47 mm, 𝐾=327 Nm, and 𝐺_Ic=724 J/m².