In this article, mode I interlaminar fracture toughness (GIC) of Vectran-stitched laminated composite is determined experimentally and computa- tionally. Critical strain energy release rates are measured by performing double can- tilever beam test on composites stitched with Vectran as stitch fiber, and are found to increase with increasing stitch thread thickness and stitch density. It is also revealed that the relationship between GIC and stitch density or stitch thread volume fraction appears to be linear. Interlaminar tension test is conducted to identify important fracture behavior of a single Vectran stitch fiber thread. The finite-element (FE) model of the stitched composite incorporates the novel four-step stitch fracture pro- cess, namely, interfacial debonding, slack absorption, fiber breakage, and pullout friction. The FE predictions of load-displacement curves and critical mode I strain energy release rates show good agreement with the experimental results. The differ- ences in interdependent stitch mechanisms between moderately stitched and densely stitched composites are discussed.
Jain, L.K. and Mai, Y.W. ( 1994). Mode I Delamination Toughness of Laminated Composites with Through-thickness Reinforcement, Applied Composite Materials , 1: 1-17.
2.
Dransfield, K.A., Jain, L.K. and Mai , Y.W. (1998). On the Effects of Stitching in CFRPs - I. Mode I Delamination Toughness, Composites Science and Technology, 58: 815-827.
3.
Tanzawa, Y., Watanabe, N. and Ishikawa, T. ( 1999). Interlaminar Fracture Toughness of 3-D Orthogonal Interlocked Fabric Composites, Composites Science and Technology , 59: 1261-1270.
4.
Tanzawa, Y., Watanabe, N. and Ishikawa, T. ( 2001). FEM Simulation of a Modified DCB Test for 3-D Orthogonal Interlocked Fabric Composites, Composites Science and Technology , 61: 1097-1107.
5.
Mouritz, A.P. and Cox, B.N. (2000). A Mechanistic Approach to the Properties of Stitched Laminates, Composites Part A: Applied Science and Manufacturing, 31: 1-27.
6.
Mouritz, A.P. , Leong, K.H. and Herszberg , I. (1997). A Review of the Effect of Stitching on the In-Plane Mechanical Properties of Fibre-Reinforced Polymer Composites, Composites Part A: Applied Science and Manufacturing, 28A: 979-991.
7.
Wood, M.D.K. , Sun, X., Tong , L., Katzos, A., Rispler, A.R. and Mai , Y.W. (2007). The Effect of Stitch Distribution on Mode I Delamination Toughness of Stitched Laminated Composites- Experimental Results and FEA Simulation, Composites Science and Technology, 67: 1058-1072.
8.
Iwahori, Y., Nakane, K. and Watanabe, N. ( 2009). DCB Test Simulation of Stitched CFRP Laminates Using Interlaminar Tension Test Results, Composites Science and Technology, 69: 2315-2322.
9.
Iwahori, Y., Ishikawa, T., Watanabe, N., Ito, A., Hayashi, Y. and Sugimoto, S. ( 2007). Experimental Investigation of Interlaminar Mechanical Properties on Carbon Fiber Stitched CFRP Laminates, Advanced Composite Materials, 16(2): 95-113.
10.
Tong, L., Mouritz, A.P. and Bannister, M. ( 2002). 3D Fibre Reinforced Polymer Composites, Elsevier Science, Oxford.
11.
Sun, X. , Tong, L., Wood, M.D.K. and Mai , Y.W. ( 2004). Effect of Stitch Distribution on Mode I Delamination Toughness of Laminated DCB Specimens, Composites Science and Technology, 64: 967-981.
12.
Sun, X. , Wood, M.D.K. and Tong, L. ( 2006). A Parametric Study on the Design of Stitched Laminated DCB Specimens, Composite Structures, 75: 72-78.
13.
Tong, L. and Sun, X. ( 2004). Bending Effect of Through-thickness Reinforcement Rods on Mode I Delamination Toughness of DCB Specimen. I. Linearly Elastic and Rigidly-perfectly Plastic Models, International Journal of Solids and Structures, 41: 6831-6852.
14.
Plain, K.P. and Tong, L. ( 2009). Traction Law for Inclined Through-thickness Reinforcement Using a Geometrical Approach, Composite Structures, 88: 558-569.
15.
Plain, K.P. and Tong, L. ( 2009). Experimental Validation of Theoretical Traction Law for Inclined Through-thickness Reinforcement, Composite Structures , 91: 148-157.
16.
Pegoretti, A. , Zanolli, A. and Migliaresi, C. (2006). Preparation and Tensile Mechanical Properties of Unidirectional Liquid Crystalline Single-polymer Composites, Composites Science and Technology , 66: 1970-1979.
17.
Pegoretti, A., Zanolli, A. and Migliaresi, C. (2006). Flexural and Interlaminar Mechanical Properties of Unidirectional Liquid Crystalline Single-polymer Composites, Composites Science and Technology , 66: 1953-1962.
18.
Friedrich, K. (1989). Application of Fracture Mechanics to Composite Materials, Elsevier Science, Oxford.
19.
Sun, C.T. (2000). The Proper Use of Fracture Mechanics in the Analysis of Composite Materials and Laminates, In: Proceedings of the Second Asian-Australasian Conference on Composite Materials (ACCM-2000), Kyongju-Korea, 18-20 August.
20.
Davidson, B.D. (1990). An Analytical Investigation of Delamination Front Curvature in Double Cantilever Beam Specimens, Journal of Composite Materials, 24: 1124-1137.
21.
Davidson, B.D. and Schapery, R.A. (1988). Effect of Finite Width on Deflection and Energy Release Rate of an Orthotropic Double Cantilever Specimen, Journal of Composite Materials, 22: 641-656.
22.
Nilsson, K.F. (1993). On Growth of Crack Fronts in the DCB Test, Composites Engineering, 3(6): 527-546.
23.
Sun, C.T. and Zheng, S. (1996). Delamination Characteristics of Double-cantilever Beam and End-Notched Flexure Composite Specimens, Composites Science and Technology, 56: 451-459.
24.
Bao, G. and Suo, Z. (1992). Remarks on Crack-bridging Concepts, Applied Mechanics Reviews, 45(8): 355-366.
25.
Sorensen, B.F. and Jacobsen, T.K. (1998). Large-Scale Bridging in Composites: R-Curves and Bridging Laws, Composites Part A: Applied Science and Manufacturing, 29A: 1443-1451.
26.
Suo, Z. , Bao, G. and Fan , B. (1992). Delamination R-Curve Phenomena Due to Damage, Journal of the Mechanics and Physics of Solids, 40(1): 1-16.
27.
Robinson, P. and Das, S. (2004). Mode I DCB Testing of Composite Laminates Reinforced With z-Direction Pins: A Simple Model for the Investigation of Data Reduction Strategies, Engineering Fracture Mechanics, 71: 345-364.
28.
Brenet, P., Conchin, F., Fantozzi, G., Reynaud, P., Rouby, D. and Tallaron, C. ( 1996). Direct Measurement of Crack Bridging Tractions: A New Approach to the Fracture Behavior of Ceramic/Ceramic Composites, Composites Science and Technology, 56: 817-823.
29.
Cotterell, B. and Mai, Y.W. (1996). Fracture Mechanics of Cementitious Materials, Blackie Academic & Professional, an Imprint of Chapman and Hall, London, UK.
30.
Chen, L., Ifju, P.G. and Sankar, B.V. ( 2005). Analysis of Mode I and Mode II Tests for Composites with Translaminar Reinforcements, Journal of Composite Materials , 39(15): 1311-1333.
31.
Rybicki, E.F. and Kanninen, M.F. (1977). A Finite Element Calculation of Stress Intensity Factors by Modified Crack Closure Integral, Engineering Fracture Mechanics, 9: 931-938.
