At present, there are two kinds of fabrics used in the composite industry: one is the woven fabric woven by rapier machine, the other is the glass fiber biaxial braided fabric. Next, let's talk about the distinction between woven fabric and glass fiber biaxial seam braided fabric.

In composite products, many woven fabrics are used: plain, twill, satin and unidirectional fabrics; It can also be used for single axial, double axial, three axial and four axial seam knitted fabrics; But do you know that these two categories are really different? Or the feeling of being confused, let's talk about the difference between these two kinds of fabrics:

1. Woven fabric

(1) Plain cloth: the weft passes through each warp alternately. Plain cloth has high stability and certain porosity, but poor shape following property, and more corrugations will also affect the mechanical properties. Especially for high-density fiber, the ripple is more obvious, so this kind of weaving method is less used to manufacture high-density fiber fabric. That is, the weft goes up and down alternately through each warp. Plain cloth has high stability and certain porosity, but poor shape following property, and more corrugations will also affect the mechanical properties. Especially for high-density fiber, the ripple is more obvious, so this kind of weaving method is less used to manufacture high-density fiber fabric.

Woven 

(2) Twill: a fabric in which one or more weft yarns alternately pass through more than two warp yarns in a fixed pattern. A continuous or discontinuous twill pattern is formed on the surface. Twill fabric has better shape following property and wettability than plain fabric, but its stability is not as good as plain fabric. At the same time, due to less ripple, the surface is smoother than plain fabric, and the mechanical properties are also higher than plain fabric.

twill

(3) Satin fabric: fabric refers to the weft yarn passing through several warp yarns in a certain order, which is classified according to the number of yarns in each fabric repeating unit, mainly including 4-pass, 5-pass and 8-pass satin. Satin fabric has less ripple, high performance, good wettability and shape following property, but poor stability. The asymmetry of satin fabric leads to more warp on one side and more weft on the other. Especially in the production of multi-layer fabric, attention should be paid to prevent stress concentration due to asymmetry.

Satin cloth

2. Glass fiber biaxial stitched fabric (GF biaxial stitched fabric) at 0 ° 、 ninety ° and ±θ All directions are lined with reinforced yarn, θ It can be at 30 °～ ninety ° The multi-layer yarn sheets are bound together by warp plain weave or chain weave. Therefore, multi axial fabric is a kind of multi-layer fabric. The fibers are laid in different directions (lining system) and along the thickness direction (binding system), forming a three-dimensional network structure composed of fiber bundles.

Glass fiber biaxial stitch fabric

(1) Tensile properties

The multi axial warp knitted fabric is characterized by good overall properties, flexible design, good tensile properties and tear resistance, especially the reinforcement of yarn along the thickness direction, which greatly improves the interlaminar properties and overcomes the weakness of poor interlaminar properties of traditional laminates. The tensile strength and modulus of fabric in any direction can be calculated by the strength and insertion direction of yarn. The fabric can be designed as isotropic or anisotropic in-plane tension. When θ=± forty-five ° The fabric can be considered as isotropic under in-plane tension.

(2) Formability of Bi diagonal fabrics

It is an important feature of the fabric deformation that the yarn cluster along the weft during the forming process. In another case, when + 45 ° At the same time – 45 ° When the yarn is rotated clockwise, the warp flat binding structure will stretch along the warp direction and shorten along the weft direction. However, the elongation along the warp direction of the flat binding fabric is very small, which makes the double oblique fabric more flexible（ ± forty-five °） It is easy to cluster along the latitudinal direction in the forming process. After hemispherical pressing, the fabric has no arching phenomenon, which indicates that the double oblique fabric has no arching（ ± forty-five °） It has good formability.

(3) Shear properties

The results show that the glass fiber biaxial stitch knitted fabric and woven fabric are under the oblique external force (45 °） Or parallel shear force is unstable. However, due to the introduction of two groups of diagonal yarns in the multi axial warp knitted fabric, the shear deformation of the fabric is restrained, so the multi axial warp knitted fabric has good shear properties.