E-mail address: kadirbilisik@gmail.com In-Plane Shear Properties of Multiaxis and Orthogonal 3D Woven Carbon/Epoxy Composites Kadir Bilisik Department of Textile Engineering, Faculty of Engineering, Erciyes University, Kayseri/Turkey E-mail address: kadirbilisik@gmail.com

OBJECTIVES In this research, multiaxis 3D weaving methods are developed to make multiaxis woven preform and composites Characterize the developed composites Identified possible end-uses

LITERATURE Researches on textile structural composite have intensively been carried out by universities, research organizations and government laboratories for applications in defense, space and civilian areas for the last two decades. Basic thrust on this type polymeric materials are attractive specific properties compared to that of metals. For instance, NASA-ACT program has encouraged the researchers to initiate fiber base advance materials [1-3].

Traditional textile structural composite materials show improved characteristics of strength and stiffness compared to those of metals and ceramics. However, they have low delamination resistance, which results in catastrophic failure[4,5]. Three dimensional (3D) woven preforms have been developed for composite materials and they show high delamination resistance and fracture toughness due to the Z-fiber reinforcement [6-8].

However, it is understood that Zfiber gives rise to some reduction in-plane properties. To improve the in-plane properties, additional fiber, which can be called bias, should be introduced to the preform at an angle. Early structures which have three sets of fibers as two bias fiber sets and filling were interlaced to each other to make single layer triaxial woven [9-11]. Later, additional axial fiber was introduced to the single layer triaxial woven fabric and was called quadrilateral fabric structure [12]. It is reported that the structure was open and had more isotropic properties compared to those of 2D traditional plain woven [11].

Multiaxis 3D woven preform and method were developed by Anahara and Yasui [13,14]. In this technique guide blocks were used to orient the bias fibers at ±45 [15]. Farley developed a technique to make multiaxis structure by using individual eye needle [16].

Mood also developed a multiaxis fabric and method based on jacquard technique [17]. Bilisik and Mohamed developed multiaxis 3D woven fabric which had many warp layers and method in which tube carriers were used to orient the bias fibers at an angle. It is found out that in-plane shear properties of the multiaxis 3D woven carbon/epoxy composite are superior to those of the 3D orthogonal woven carbon/epoxy composite [18,19]. Uchida and coworkers made prototype multiaxis 3D weaving based on Anahara’s guiding block principles [20,21]. Recently, Bryn and Nayfeh and coworkers developed the techniques to make multiaxis fabric used as connectors and joint elements for defense related product [22,23].

Materials and Methods Figure . Multixias 3D woven unit cells

Figure. 3D Orthogonal woven unit cell

Figure . Actual view of multiaxis 3D weaving zone according to tube-carrier method (right). Figure . Multiaxis 3D carbon woven perform (P2) from tube carrier weaving (left side).

Figure . Bias yarn path in the preform surface; zig-zag pattern from linear movement of the tube-rapier (a) and edge-to-edge pattern from rotational movement of tube-carrier (b). Figure . Total and directional fiber volume fractions of preform types based on tube-rapier and tube-carrier methods.

Figure . Schematic views of bias units based on tube-carrier and tube-rapier

Table . Preform elastic constants from tube rapier weaving and tube carrier weaving

Figure. Directional modulus of elasticity of preform types. Figure Figure . Directional modulus of elasticity of preform types. Figure . Directional modulus of rigidity of preform types.

Table. Specification of composite materials

Figure . Top views of the multiaxis wherein 3D carbon fiber woven preform (a), top views of the multiaxis 3D carbon fiber woven preform wherein uncovered bias yarn area and bias turning point fromşbias to bias orientation (b), cross-sectional view of the multiaxis 3D carbon fiber woven perform (c), top views of the 3D orthogonal carbon fiber woven perform (d), cross-sectional views of the 3D orthogonal carbon fiber woven preform (e), magnifications: (a), (b), (e): 6.7, (c): 15, (d): 10.

Figure . Cross-sectional view, and longitudinal warp side view of the multiaxis 3D woven carbon/epoxy composite. Figure . Cross-sectional view, and longitudinal warp side view of the multiaxis 3D woven carbon/epoxy composite.

Figure. Volume fraction of the multiaxis 3D woven preform (left) Figure . Volume fraction of the multiaxis 3D woven preform (left). Figure . Flextural strength (a) and bending modulus (b) of multiaxis and orthogonal woven composites (right).

Figure . Flextural strength (a) and bending modulus (b) of multiaxis and orthogonal woven composites (left). Figure . Bending failure to the warp side of the multiaxis 3D woven composite (a), bending failure to the warp side of the 3D orthogonal woven composite (b) (right).

Figure . Interlaminar shear strength of multiaxis and 3D orthogonal woven composites (left). Figure . Interlaminar shear failure to the warp side (a), and to outside surface (b), of 3D woven composite (right).

Figure . In-plane shear strength of multiaxis 3D woven and 3D orthogonal woven composites (a), in- plane shear modulus of multiaxis 3D woven and 3D orthogonal woven composites (b), in-plane shear stress – strain curve for both multiaxis and orthogonal woven composites (c).

Figure . In-plane shear failure (a), in-plane shear failure at surface (b) of the multiaxis 3D woven composite and in-plane shear failure (c) of the 3D orthogonal woven composite.

Conclusions Multiaxis 3D woven carbon preform was developed and consolidated with epoxy resin. The properties of the multiaxis 3D woven composites were compared to those of 3D orthogonal woven composites. It was found that by the addition of ±bias yarns to the surface of the multiaxis 3D woven perform, the in-plane shear strength and modulus of the structure were increased. However, the other properties such as bending and interlaminar shear strength of the structure were decreased compared to those of the 3D orthogonal woven composite.

These results have shown that the mechanical properties of the woven structure are strongly influenced by yarn orientation. Consequently, newly developed multiaxis 3D woven composites will always be a compromise based on the end use requirement, and therefore, optimization of the structure becomes important.

REFERENCES 1. Dow, M.B. and Dexter, H.B. (1997). Development of stitched, braided and woven composite structures in the ACT Program at Langley Research Centre (1985 to 1997). NASA/TP-97-206234.   2. Kamiya, R., Cheeseman, B.A., Popper. P. and Chou, T.W. (2000). Some recent advances in the fabrication and design of three dimensional textile preforms: A review, Composite Science and Technology, 60: 33-47. 3. Chou, T.W. (1992). Microstructural design of fibre composites, New York: Cambridge University Press. 4. Dow, N.F., Tranfield, G. (1970). Preliminary investigations of feasibility of weaving triaxial fabrics (Doweave), Textile Research Journal, 40(11): 986-998. 5. Cox, B.N., Dadkhah, M.S., Morris, W.L. and Flintoff, J.G. (1993). Failure mechanisms of 3D woven composites in tension, compression and bending, ACTA Metallurgica et Materialia, 1993. 6. Brandt, J., Drechsler, K. and Arendts, F.J. (1996). Mechanical performance of composites based on various three–dimensional woven fibre performs, Composites Science and Technology, 56: 381-386.

7. Dexter, H. B. and Hasko, G. H. (1996) 7. Dexter, H.B. and Hasko, G.H. (1996). Mechanical properties and damage tolerance of multiaxial warp-knit composites, Composites Science and Technology, 51: 367-380.  8. Anahara, M. and Yasui, Y. (1992). Three dimensional fabric and method for producing the same, US Patent 5137058, August 11. 9. Mohamed, M.H. and Bilisik, A. (1995). Multilayered 3D fabric and method for producing, US Patent 5465760, November 14.  10. Uchida, H., Yamamoto, T. and Takashima, H. (2000). Development of low cost damage resistant composites, http://www.muratec.net/jp. 11. Bilisik, A. and Mohamed, M.H. (1994). Multiaxis 3D weaving machine and properties of multiaxial 3D woven carbon/epoxy composites, The 39th International SAMPE Symposium and Exhibition. 12. Bilisik, K. (2010). Multiaxis 3D woven preform and properties of multiaxis 3D woven and 3D orthogonal woven carbon/epoxy composites, Journal of Reinforced Plastics and Composites, 29 (8): 1173-1186.

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