Deformability of a non-crimp 3D orthogonal weave E-glass composite reinforcement Valter Carvelli a,⇑ , Juan Pazmino a , Stepan V. Lomov b , Ignaas Verpoest b a Department of Structural Engineering, Politecnico di Milano, Piazza Leonardo da Vinci 32, 20133 Milano, Italy b Department of Metallurgy and Materials Engineering, Katholieke Universiteit Leuven,Kasteelpark Arenberg, 44, B-3001 Leuven, Belgium article info Article history: Received 20 June 2012 Received in revised form 6 September 2012 Accepted 10 September 2012 Available online 20 September 2012 Keywords: 3D composite reinforcement A. Fabrics/textiles A. Glass fibers C. Deformation abstract Deformability of a single-ply E-glass non-crimp 3D orthogonal woven reinforcement (commercialized under trademark 3WEAVE Ò by 3Tex Inc.) is experimentally investigated. The study is focused on the understanding and measurement of the main deformation modes, tension and in plane shear, which are involved during draping of composite reinforcements by: (i) uniaxial and biaxial tension; (ii) in-plane shear investigation using uniaxial bias extension and picture frame tests; and (iii) measurements of the fabric thickness variation during shear. The test methods common for 2D fabrics are validated for the thick 3D reinforcement. The obtained results represent a data set for the simulation of a forming process with the 3D reinforcement. Ó 2012 Elsevier Ltd. All rights reserved. 1. Introduction In any composite manufacturing process a crucial step is the forming of the initial planar reinforcement into a desired (three- dimensional) shape. After shaping, the formed reinforcement is injected with resin and consolidated. In this process, the deforma- bility of the reinforcement plays a key role in definition of the fiber orientations, which influences permeability of the preform and fi- nally defines the mechanical quality of a composite component. Therefore, the knowledge of deformation behavior of a dry com- posite reinforcement is important to predict and avoid defects (e.g. wrinkling) in complex preform shapes. Focusing on continuous fiber materials, many investigations available in the literature [1,2] are mainly dedicated to the defor- mability of textile reinforcements with 2D interlacements, these being adapt for producing three-dimensional shapes. In spite of the fast growing interest for 3D orthogonal interlock woven reinforcements in the composites industry for a broad range of applications [3], the deformation properties of these reinforce- ments are not deeply known and investigated. Recently, Boisse et al. [4–6] have reported experimental data and modeling of deformability of a specific type of angle interlock carbon fabrics for fan blades applications. The authors are not aware of similar studies for orthogonal 3D woven reinforcements. Their behavior, due to a specific geometry of Z-binding and extreme straightness of the stuffing warp and weft yarns [7,8], is quite different from the tight heavily interlaced angle interlock weaves [9]. In this work, the deformation resistance of a dry single-ply E-glass non-crimp 3D orthogonal woven reinforcement is experi- mentally investigated. The deformation during extension is inves- tigated under uniaxial and biaxial loading in the in-plane tows directions (i.e. warp and weft). The biaxial tensile tests provide information on the initial nonlinear stiffening due to the low crimp in the tows. The effect of different velocity rate ratios is also investigated. Particular attention is dedicated to the behavior during shear loading because this is considered the primary deformation mech- anism in the reinforcement shaping [10]. The mechanisms occur- ring when the material is subjected to in-plane shear is studied by two different tests, namely uniaxial bias extension and picture frame. The non-linear responses of the material to both tests are compared in terms of macroscopic shear force vs. shear angle. The shear deformation is observed and measured at the macro- scale, by means of digital image correlation technique. Furthermore, picture frame tests with laser thickness registra- tion were performed in order to estimate the fabric thickness var- iation (directly connected to fiber volume fraction) due to in-plane shear loading and therefore during draping processes. The obtained results constitute a data set for the simulation of forming processes with such 3D reinforcement. 2. Material The fabric is a single-ply E-glass non-crimp 3D orthogonal wo- ven reinforcement (commercialized under trademark 3WEAVE Ò by 3Tex Inc.). The fiber architecture of the preform has three warp and four weft layers, interlaced by through thickness (Z-directional) 0266-3538/$ - see front matter Ó 2012 Elsevier Ltd. All rights reserved. http://dx.doi.org/10.1016/j.compscitech.2012.09.004 ⇑ Corresponding author. Tel.: +39 0223994354; fax: +39 0223994369. E-mail address: valter.carvelli@polimi.it (V. Carvelli). Composites Science and Technology 73 (2012) 9–18 Contents lists available at SciVerse ScienceDirect Composites Science and Technology journal homepage: www.elsevier.com/locate/compscitech