| Rubber is an important kind of damping material because of its viscoelastic property, which has been applied in the field of aviation, aerospace, transportation, mechanical engineering and construction industry. However, its mechanical property is so poor that it is very difficult to be used as structural materials independently. In order to get a structural and functional material, a new damping composite was designed and studied in the dissertation based on the theory of composite and damping mechanisms. The ternary composite composed of glass fiber (GF), lead (Pb) and rubber (R) is named as glass-fiber–cored lead-wire(GF/Pb-wire) or woven GF/Pb-wire(GF/Pb-net) reinforced rubber composite (GF/Pb/R).The properties of four kinds of composites with different structures were studied systematically in the dissertation. They were horizontally layered GF/Pb-net reinforced rubber composite (H-GF/Pb/R), vertically layered GF/Pb-net reinforced rubber composite (V-GF/Pb/R), short GF/Pb-wire reinforced rubber composite (S-GF/Pb/R) and continuous GF/Pb-wire reinforced rubber composite (T-GF/Pb/R).The mechanical properties and damping properties of the composites under compressional loading and shear loading were studied by measuring their mechanical hysteresis loops and vibration transmissibility. And the damping mechanism of the composites was analyzed. The experimental results show that the compresssional properties (including mechanical property and damping property under compressional loading) of rubber are improved together by using GF/Pb-wire (or GF/Pb-net) as the reinforcement. But the shear properties don't change obviously. The improvement of the damping property of GF/Pb/R dues to varied damping mechanisms, including material damping, interfacial micro-slippage damping and microscopic plastic deformation damping of Pb. And their contribution to the damping property of the composite is affected by many factors, such as interface area, interface bond strength and the distribution of stress in the composite, and so on.Furthermore, it was also studied that the influences of frequency, structural parameters, component properties and application conditions to the mechanical properties and damping properties of H-GF/Pb/R, V-GF/Pb/R, S-GF/Pb/R and T-GF/Pb/R.By studying the influence of the volume fraction of GF/Pb-wire (or GF/Pb-net)(VGF/Pb) on the mechanical properties and damping properties of the composites, it tells that the compressional properties of H-GF/Pb/R and V-GF/Pb/R improve with increasing the volume fraction of the GF/Pb-net. However, their shear properties change little. The dynamic stiffness of T-GF/Pb/R increases and its loss factor decreases a little when the volume fraction of GF/Pb-wire increases..By studying the influence of composite structure on the composite properties, it is concluded as follows: the compressional stiffness and loss factor of H-GF/Pb/R change a little with the change of GF/Pb-net layer position in the composite, while those of V-GF/Pb/R change little with the variation of the angle between the neighbouring GF/Pb-net layers. The combination property of H-GF/Pb/R is the best when the GF/Pb-net lies at the middle of the composite. And the property of V-GF/Pb/R is perfect when the angle between layers is 0°and the GF/Pb-nets are laid uniformly.By studying the influence of the interfacial bond strength between GF/Pb-wire and rubber on the properties of composites,it tells that the interface properties are important factors to influence the properties of GF/Pb/R because the changes of interface status after vibration are different for composites with varied interfacial bond strength. The small gaps at the interface enlarged immediately under the cyclic loading when the interface bond strength was weak. However, GF/Pb-wire and rubber still combined tightly after vibration when the interface was bonded strongly. Thus, the energy dissipations were different in composites with varied interface bond strength that their properties differ obviously. The compressional mechanical properties of H-GF/Pb/R and V-GF/Pb/R improve with the improvement of the interfacial bond strength, while their loss factors change irregularly. The loss factor of H-GF/Pb/R is the maximum when the interface bond strength is medium, while that of V-GF/Pb/R is the maximum when the interface is bonded weakly.By studying the physical properties of GF/Pb-wires with different ingredient and different diameter and analyzing the composite properties composed of those GF/Pb-wires, it is concluded that plastic deformation is easier to take place in Pb than in PbSn, therefore more energy dissipation comes into being in the former. So GF/Pb/R prepared with Pb has higher damping properties. Because the interface area and the distribution of GF/Pb-wire (GF/Pb-net) vary with the change of GF/Pb-wire diameter in the composite, the mechanical property and damping property of GF/Pb/R change accordingly. When the volume fraction of GF/Pb-wire or GF/Pb-net is fixed, the mechanical properties and the damping properties of H-GF/Pb/R and V-GF/Pb/R improve with the increase of GF/Pb-wire diameter. And the properties of S-GF/Pb/R change little. While the mechanical property decreases and the damping property changes irregularly for T-GF/Pb/R.By testing the properties of composites under different loading and different vibration amplitude, their vibration control effects were studied. It reveals that the compressional stiffness and loss factor increase while increasing the precompression and decrease while increasing the vibration amplitude. The dynamic stiffness of the composites increases with increasing the frequency. The loss factor increases when the frequency is lower than 8Hz and reaches the peak value at 8Hz, and then it decreases.By comparing the properties of H-GF/Pb/R, V-GF/Pb/R, S-GF/Pb/R and T-GF/Pb/R with 4% volume fraction of GF/Pb-wire or GF/Pb-net within the range of 3~20Hz under the same condition, it is concluded that the compressional mechanical properties of H-GF/Pb/R and V-GF/Pb/R improve more than the others, and their stiffness increase by 53%~57% and 48%~50% respectively. The improvement of the damping property of V-GF/Pb/R is the most distict among the four composites, and its loss factor increases by 24%~47%.In addition, on the basis of energy method, two finite element models composed of rubber lamina and GF/Pb-net reinforced rubber lamina were developed to predict the mechanical properties and the damping properties of H-GF/Pb/R and V-GF/Pb/R in virtue of software ANSYS, respectively. Another finite element model composed of rubber and two orthogonal GF/Pb-wires was also developed to analyze the effect of the loss factor, the modulus and the thickness of the interface on the damping properties of the composite theoretically. The finite element models were proven valid because the predicted results agree with the experimental results well. It is found that the damping properties of GF/Pb/R cannot be improved unless the interface modulus is over 1.25×108Pa. And the damping property of the interface has greater effect on the damping property of GF/Pb/R than its modulus and thickness.At last, four composites with the optimized structure parameters were prepared to discuss their vibration control effect in engineering application. The stiffness of H-GF/Pb/R improves by 165%~198%, and the loss factor of V-GF/Pb/R increases by 42%~68% within the range of 3~20Hz. Vibration test shows that the vibration transmissibility of the system with composites is only half of that of the system with rubber. That's to say, the composite has greater vibration reducing capability. GF/Pb-nets reinforced rubber can meet the demands of stiffness and insulation for railroad damping cushions while the pure rubber can not. What is more, the producing cost is also reduced.
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