The Influence Of Structural Parameters On Tensile Properties Of 2.5D Woven Reinforcement Materials

2.5D woven composite is a new material developed in the recent years. It has excellent interlayer properties and good anti-impact properties, all these good properties bring a bright tomorrow for 2.5D woven composite. It can molding at one time, producing automatic and continuous, improving of efficiency, reducing the production cost, extending its further application fields. So, people pay more attention to the development and applications of 2.5D woven composite.The woven composite in its nature is a structure, its properties mainly decided by its structure, so research the relationship between structure parameters and property is significant. The composite's structure is the micro-structure of reinforcement materials. Reinforcement materials afford principal stress and secondary stress during use. Given the structure of 2.5D fabric is very particular, weft in the fabric be linear distribution, the form of construction major decide by the warp. So system description the relationship between structure parameters and tensile property is significant. It can provide directly theoretical basis for engineers to choose correct micro-structure. This paper studied 2.5D woven reinforcement materials. Using tracing method and image processing to get trend curve and section shape of warp in Orthogonal superficial interlock fabric. According to the section trace line shape of warp, we can find the warp in 2.5D woven reinforcement materials assumes a sine distribution, the warp's section is racetrack shaped. A new model is developed by means of true form. The model has the obvious physical concept and can be used to analysis directly the influences of the structural parameters on reinforcement materials. The relationship among fiber volume fraction Vf , binding depth Nft ,orientation angle 0b, yarn undulation of warp direction, tensile strength, modulus of elasticityin tension are studied by the above theoretical model, in order to understand the affection of structural representative parameters on composite properties. It indicates that: when the two materials are both use angle binding structures, Orientation angles are equal, the warp tensile strength will decline with binding depth Nft increases; when the two materials using different binding structures, and have the equal binding depth, the warp tensile strength will decline with yarn undulation of warp direction q increases; when the two materials are both use Orthogonal binding structures, the warp tensile strength will determine by yarn undulation of warp direction q and fiber volume fraction. We designed four kinds of reinforcement materials with different structures, than used the same glass fiber, the same warp density, weft density and layer number to weave 2.5D woven reinforcement materials. The result of the warp direction properties indicates that: angle superficial interlock fabric and angle deep interlock fabric are both angle interlock fabric, because of the small binding depth Nft, the angle superficial interlock fabric's tensile strength and modulus of elasticity in tension are better than angle deep interlock fabric's. Compare the angle superficial interlock fabric with angle deep interlock fabric, because of the reduce of the warp flection degree q, angle superficial interlock fabric's tensile strength and modulus of elasticity in tension with angle deep interlock fabric. As mostly warps have teeny warp flection degree q, the Orthogonal interlock fabrics tensile strength and modulus of elasticity in tension are excellent. The result showed the validity of the theoretical analysis.This topic analysed the relationship between 2.5D woven materials' structural parameter and warp direction tensile properties. The experiments and analysis results enriched the database of 2.5D woven composites' mechanical properties. This provides a basis for 2.5D woven composites.