Study On The3D Integrated Hollow Woven Structure And The Composites Rigidity

By using modern science,3D hollow woven composites have become lighter, stronger,more designable and more comprehensive. Consequently, the3D hollow woven composites aregetting more and more popular, and become the developing emphasis of composite materials.3Dhollow woven composites overcome the defects of easy debond between skin and core, poorimpact resistance and weak shear retardant property in comparison with traditional sandwichcomposites.3D hollow woven composites can be used in aerospace, ocean ship, automobile andother industrial engineering institutions. The paper researched design of the hollow structure,weaving of the performs, molding process of the performs and the material selection of3Dhollow woven composites, and stressed on tensile stiffness and bending stiffness of the3Dweaving hollow structure composites. The content and main conclusions of this paper are asfollows:(1) Through analyzing the performance of raw reinforced fiber yarn, carbon fiber,high-tenacity polyethylene fiber, industrial polyester fiber were chosen as the reinforcedmaterials of3D hollow woven composites. In order to improve the performance of weaving, thethesis analyzed the orthogonal, pseudo-orthogonal, angular interlocking and open structure,which are four typical3D woven structures. And the orthogonal structure was used as basicstructure pattern to design several different3D weaving hollow structures.(2) To reduce damage pilling and knotting reinforced fibers materials in the weavingprocess,and to improve the performance of weaving efficiency,reinfoced fibers are coated by3.33tex polyester yarn.The thesis weaved three kinds of preforms for the3D hollow wovencomposites,which are "hexagon","triangle",and"I",on the reformed regular machine.(3) Vacuum Assisted Resin Infusion was used to mold the hollow integrated fabric. In thewhole curing system, the weight ratio of resin, curing agent, accelerating agent should be100:1:2,the air pressure of vacuum pump should be set to-0.08MPa, and the time of curing should be 15-25minutes.(4) The innovative tested the property of tensile and bending of3D weaving hollowstructure composites, and the result indicates that there is big difference between the warp andweft property of3D weaving hollow structure composites, and the weft property is better thanthe warp. The most important reason is that there are much more reinforced fibers in weftdirection than the ones in warp direction. In other words, the arrangement is much more closelyin weft direction than that in warp direction. When a load is applied, the strength in weft is muchmore even, and there is no obvious weak stress area in weft. Consequently the property in weftof3D weaving hollow structure composites is better than the one in warp.(5) The result of testing the property of tensile and bending of3D hollow wovencomposites demonstrates that the performance of3D hollow woven composites decrease in thesequence of "hexagon,""triangle","Ι", which are the same composite but in different sectionshape. While the performance decrease in the sequence of carbon fiber, high-tenacitypolyethylene fiber, industrial polyester fiber, which have the same hollow structure. The mainreason is that there is positive liner correlation between the property of the composites and thatof reinforced fiber, when the combined degrees of reinforced fiber and resin are the same.