3D weaving

Three dimensional woven fabrics are fabrics that could be formed to near net shape with considerable thickness. There is no need for layering to create a part, because a single fabric provides the full three-dimensional reinforcement. The 3-D woven fabric is a variant of the 2D weaving process, and it’s an extension of the very old technique of creating double and triple woven cloth. 3D weaving allows the production of fabrics up to 10 cm in thickness.^[1] Fibers placed in the thickness direction are called z-yarn, warp weaver, or binder yarn for 3D woven fabrics. More than one layer of fabric is woven at the same time, and z-yarn interlaces warp and woof yarns of different layers during the process. At the end of the weaving process, an integrated 3D woven structure, which has a considerable thickness, is produced.^[2]

Classification of 3D woven fabrics

There are several types of 3D woven fabrics that are commercially available; they can be classified according to their weaving technique.^[3]

1. 3D woven interlock fabrics, are 3D woven fabrics produced on a traditional 2D weaving loom, using proper weave design and techniques, it could either have the weaver/z-yarn going through all the thickness of the fabric or from layer to layer.
2. 3D orthogonal woven fabrics, are 3D woven fabrics produced on a special 3D weaving loom. The process to form such fabric was patented by Mohamed and Zhang.^[4] The architecture of the 3D orthogonal woven fabric consists of three different sets of yarns; warp yarns (y-yarn), weft yarns (x-yarn), and (z-yarn). Z-yarn is placed in the through-thickness direction of the perform. In 3D orthogonal woven fabric there is no interlacing between warp and weft yarns and they are straight and perpendicular to each other. On the other hand, z-yarns combine the warp and the weft layers by interlacing (moving up and down) along the y-direction over the weft yarn. Interlacing occurs on the top and the bottom surface of the fabric.^[5][6]

Advantages

• 3D woven fabric are very useful in applications where the composite structure is subjected to out-of-plane loading, thanks to the extra strength provided by the z-yarn in the through thickness dimension. Thus it can better resist delamination, which is the separation of layers due to out-of-plane forces.^[7]
• 3D woven fabrics have a high formability, which means they can easily take the shape of the mold in case of complex composite designs.^[8]
• 3D woven fabrics have a highly porous structure, which decreases resin infusion time.^[9]
• 3D orthogonal woven fabrics have less or no yarn crimp (the difference in length of yarn, before and after weaving); therefore, mechanical properties of fibers are almost fully utilized in warp and weft directions. Thus, it could benefit from the maximum load carrying capacity of high performance fibers in these directions.^[10]
• The shape of 3D woven fabrics can be tapered in all three directions during the weaving process, producing near net shape fabrics such as I-beams and stiffeners. This means that these preforms could be placed directly in the mold without any additional labor work.^[11]
• There is no need for layering to create a part, because the single fabric has a considerable thickness that provides the full three-dimensional reinforcement.^[12]
• The 3D woven fabric can be molded into different shapes and can be used in biological applications to create replacement tissues^[13]

References