Preparation And Mechanical Properties Of Flax/Polypropylene2.5D Woven Composite

2.5D woven composite materials are a special case of3D woven composite materials. Itmainly consists of a warp system and weft system. In the Woven fabrics, the weft yarns werelinear and the warp yarns were inserted between weft yarns at a certain angle. The angle andbinding depth that the warp yarns were wove are two important parameters of2.5Dcomposites. They partly determine the performance of the2.5D woven composites.As with traditional3D composite,2.5D woven composite material has excellentcomprehensive performance, such as characteristic of holism, not easy to delaminate,excellent resistance to impacts. And it has already achieved Continuous production. Thus2.5D woven composite material has broad application prospects. The subject is focus onresearching the2.5D woven composites, mainly its preparation&mechanical property. Thefollowing contents are included in this research.（1）The preparation of2.5D woven composites. First step, PP filaments were wrappedin the flax surface to form PP/flax covered yarn. The second step, The covered yarns wereused as warps and weft yarns to weave three typical2.5D woven fabrics(deep crossing linking,straight shallow-crossing linking and the curved one) on SU111automatic rapier loom. Thethird step, the preparation of composite materials. The woven fabrics were made into PP/flaxcomposites by hot pressing in the Carver hot-pressing equipment in a certain temperature andpressure conditions.（2）The microstructure analysis of2.5D woven composite. The first step, use ANSYSfinite element software builds a structural model of2.5D woven composite. Then with thehelp of the structural model, the microstructure of the material was analyzed. Researchshowed that the orientation angle of curved shallow-crossing linking was larger than straightshallow-crossing linking; the orientation angle of deep crossing linking was the smallest one.The warp flexion of shallow-crossing linking was significantly larger than shallow crossdirectly linking; and the warp flexion of shallow cross directly linking was very close to deepcrossing linking.（3）The tensile property of2.5D woven composite. First, tensile property was tested byusing Instron universal testing machine. Then, discussed the structural parameters’ effect onits’ mechanical properties. The results showed that warp direction tensile property of deepcrossing linking woven fabrics turned out to be best, and those of curved ones were worst.The weft direction tensile property of the three2.5D woven fabrics just differed little. Warpdirection tensile property of straight shallow-crossing linking composites were best, while thedeep crossing linking ones were worst. The weft direction tensile property of the three2.5Dwoven composites just differed little.（4） Low-velocity impact performance of2.5D woven composites. First Thelow-velocity impact performance of2.5D woven composites was tested by using the lowvelocity impact test system which designed by myself. Then, discussed the structuralparameters’ effect on its’ Low-velocity impact performance. When the2.5D wovencomposites resist to low speed impact (1J), curved shallow-crossing linking absorbed0.816J energy, and the biggest load was the575.1N; deep crossing linking absorbed0.771J energy,and the biggest load was the301.74N.