Study On The Preparation And Preformance Of Three-dimensionally Sewed Sandwich Structural Composites

Damping composite material is a kind of advanced composite materials which developed in recent years. As a result of its good strength and stiffness, it is widely used in many fields, involving aviation and aerospace, mechanical power, transportation, power electronics, military and instrumentation industry and other fields; it is of a great importance to develop the national economic construction, to increase its defense equipment effectiveness, and to improve people's living environment and quality. Preparing damping composites with good strength and stiffness as well as well damping capacity by combined different materials now became the new trend of development of damping materials.To integrate the strength and damping function into an all-in-one structure, now the most useful structure is the "sandwich structure". This kind of structure is weak in interfacial property. It is easily destroyed by the separation of the structure layer and the damping layer.To solve this problem, we decide to open holes through the structure layer and damping layer, sew them with the yarn by lock-type and make them together as a whole one.By designing damping layer of 3D-sewed sandwich structure, choose different damping layers to get different samples. Comparing data from different samples, we study of various factors on the performance of the overall structure and analyze the reasons for this result. The factors are the sewing structure, structure layer, sewing type and damping layer. In order to get a better sample, we can use the better structure lay material, decreasing the sewing distance, better damping layer material and use the flexible epoxy resin matrix composite material. Reinforcing the interface of the structure lay and damping lay can also improve the properties of the samples.By using the existing materials, we obtained the best design is the resin matrix surface layer, the flexible epoxy resin matrix kevlar sheet reinforced composite material damping layer inside, kevlar yarn sewing line,1.5cm sewing distance. The damping ratio of it is 3.62%, bending strength is 301.24MPa, bending modulus is 15.34GPa, impact toughness is 356.12kJ/m2.