Studies On The Vibration And Damping Properties Of High-performance Fibers Reinforced Epoxy Composites

With the development of science and technology, mechanical equipment in the field of aerospace and engineering tends to high-speed and high-efficiency, which leads to more and more serious vibration and noise problems. Therefore, reducing the vibration and noise by using damping materials has caused the attention of people increasingly. Fiber reinforced resin matrix composite has good damping capability and excellent mechanical properties, which enables it to be a research hotspot in damping materials. This paper researches on the vibration damping performance of the fiber reinforced epoxy composites, aiming to explore how to improve the vibration damping properties of the composites by optimal structure and interface design.In this paper, we prepared the two-dimensionally(2D) and three-dimensionally(3D) braided carbon/Kevlar hybrid fiber reinforced epoxy composites(CF/KF/EP) through the resin transfer molding(RTM) process. We studied the influences of CF surface modification, fiber hybridizing and rubber coating on the mechanical and vibration damping properties of the composites. In addition, we have investigated the regulating mechanism of fiber hybridizing and interfacial modification on the mechanical and vibration damping properties of the composites.Results indicated that, appropriate CF surface oxidation treatment and fiber orientation angle can improve the mechanical and vibration damping properties of the composites. 2D-CF/KF/EP composites had obvious positive hybrid effect on its damping performance. When the carbon fiber volume content(VCF) was 15%, the damping loss factor(?) reached 0.048, more than the value calculated by mixed law. Different stacking sequence in CF/KF/EP laminated composites can change the two parameters of hybrid interfaces and the outmost layer fiber type. The forth has a greater influence on the damping loss factor, while the latter has obvious effects on the natural frequency of the composites. In the 3D braided hybrid composites, most of the mechanical properties enhanced with the increas e of VCF, except the ?. When the VCF was 19%, the ? presented negative hybrid effect due to the formation of ideal hybrid interface. Study on the effect of the braiding form on the vibration damping properties of the composites indicates that, different braiding form will influence the deformation in the process of each order vibration, resulting in different damping loss factor between CF3D/EP and CF2D/EP composites.After modification by rubber coating, the damping loss factor of the composites increased by 120%, reaching to 0.068. These results indicated that fiber surface modification by rubber coating is an important means to optimize the vibration and damping properties of the composites.