以碳纤维增强复合材料(CFRP)为代表的先进复合材料具有高比强度、比模量等优点，在工业和装备领域代替传统材料得到了越来越广泛的应用。因此，传统材料面临的振动和噪声问题在复合材料中同样突出。振动和噪声会影响人们的工作与生活环境，降低系统的性能和生产效率，破坏设备运行的稳定性和可靠性，长期的振动还会对结构造成损伤，引起结构有效寿命的下降。复合材料构件以薄壁件为主，在倾向于高速化的应用领域中，振动和噪声的负面影响会表现得愈发明显。复合材料的减振降噪研究具有重要的意义。 复合材料的减振降噪性能依赖于其阻尼和模量。模量的提高可以改善低频下的减振降噪性能，而良好的阻尼性能则起到改善全频域范围内复合材料减振降噪性能的作用。因此，减振降噪要求复合材料兼具高阻尼和高刚度，而高刚度也是复合材料作为结构材料的必然要求，这就要求对结构和阻尼进行一体化设计。复合材料结构阻尼一体化的研究主要集中在“层间式”结构，这种结构来源于传统的附加式阻尼结构，直接将阻尼层插入到复合材料层间。粘弹性阻尼层共固化复合材料以橡胶作为阻尼层，存在整体刚度下降、界面结合力低、耐热性差、阻尼层易老化等问题；其他非橡胶类的结构阻尼复合材料等会造成整体厚度、质量和工艺成本增加。复合材料具有多组分、多界面和可设计性强的优点，在性能改善上具有很大的自由度，充分利用这些特点完全可以设计出不依赖于层间插层的结构阻尼一体化复合材料。因此，本文力图跳出插层式的改性思维，明确纤维增强复合材料的阻尼来源和机理，从纤维增强复合材料的基本结构(基体、界面和纤维)出发考虑复合材料的结构阻尼一体化设计。 本文中基于基体的结构阻尼一体化通过纳米粒子的添加来实现。选择了3种具有代表性的纳米粒子来研究其对环氧基体力学性能、阻尼性能和热性能的影响规律和机理：(1)多壁碳纳米管(Multi-Walled Carbon Nanotubes，MWCNT)。采用基于溶剂法的高速剪切法将不同尺寸的MWCNT分散到环氧基体中。通过理论计算对MWCNT的分散过程进行了定性的分析。对比Halpin-Tsai模型的计算结果和拉伸测试结果判断MWCNT在基体中是否得到了良好的分散。测试结果表明MWCNT的添加能够实现环氧基体力学性能和阻尼性能的同步增强。环氧基体的拉伸模量最大提高达到了20％，拉伸强度最大提高了8％，25℃ 1 Hz下的损耗因子最大提高了56％。对纤维状纳米粒子界面摩擦的产生及影响因素进行了分析。大长径比和大比表面积的MWCNT对力学性能和阻尼性能的增强效果更好。团聚体对基体的力学性能和阻尼性能均有负面影响。而MWCNT的尺寸和团聚体对基体的玻璃化转变温度(T〓)的影响规律和对力学性能、阻尼性能的影响完全相反。(2)石墨型氮化碳g-C₃N₄。以尿素为前驱体，通过热缩聚法制备g-C₃N₄，并进行了一系列的表征测试，随后将其作为一种新型填料通过高速剪切分散到环氧基体中。改性后环氧基体的拉伸模量和弯曲模量分别提高17.29％和12.38％， T〓提高了4-5℃，初始热分解温度(T〓)和50％的热分解温度(T〓)均提高了15℃。机械性能和热性能的显著改善归功于微卷曲结构、大比表面积形成的机械锁合作用以及天然携带的氨基基团与环氧基团反应形成的化学键。改性后的基体25℃ 1 Hz下的损耗因子由0.035增加到0.049，阻尼性能增强可能源于层间滑动摩擦、层间氢键周期性断裂与重建和微型约束层阻尼结构耗能的综合作用。(3)核壳结构纳米橡胶(Core-Shell structure nano-Rubber，CSR)。CSR是一种新型的环氧增韧剂，鉴于基体增韧与阻尼之间的密切联系，将其和环氧基体混合制备纳米复合材料。测试结果表明10 wt％添加量的CSR能够将基体的冲击强度从22.33±4.77 KJ／㎡增加到36.89±4.43 KJ／㎡，同时拉伸性能和弯曲性能的保持率较高，T〓基本保持不变，但是同时CSR的添加对基体的阻尼性能也几乎没有影响。球形结构限制了CSR与基体的界面摩擦耗能以及其本身粘弹性的发挥。最后，选择综合性能最好纳米粒子改性基体制备纤维增强复合材料，测试结果表明MWCNT和g-C₃N₄改性基体能够实现纤维增强复合材料结构和阻尼性能的增强。 基于界面的结构阻尼一体化通过在纤维界面引入多尺度纳米粒子实现。基于对g-C₃N₄的研究，通过原位合成制备了负载g-C₃N₄的碳纤维来改善纤维增强复合材料的性能。g-C₃N₄的引入极大地提高了碳纤维表面的粗糙度和湿润性，增加了纤维表面官能团的数量。测试结果表明碳纤维表面自由能增加了67.81％，界面剪切强度(IFSS)由44.62 MPa增加到73.41 MPa，层间剪切强度(ILSS)从51.84 MPa增加到72.09 MPa。复合材料的拉伸强度从564.91 MPa提高到675.31 MPa，拉伸模量从50.12 GPa提高到58.37 GPa。弯曲强度从719.51 MPa增加到795.13MPa。弯曲模量从47.14 GPa增长到51.83 GPa；冲击测试中总的吸收能量从1.14 J增加到1.78 J。玻璃化转变温度由116.71℃提高到121.34℃。改性后纤维增强复合材料的损耗因子达到了未改性前的2.2倍，用于表征结构阻尼性能的优值提高了114.1％。 基于纤维的结构阻尼一体化通过混杂的方式将高阻尼纤维引入到碳纤维复合材料中实现。本文设计了一系列碳纤维／芳纶纤维混杂结构，测试表明混杂复合材料具有折中的力学性能和阻尼性能。混杂复合材料的拉伸模量仅由混杂比决定，拉伸强度和失效行为同时由混杂比和铺层结构决定。位于铺层中心位置的连续多层碳纤维能够产生正向拉伸强度混杂效应。混杂复合材料的弯曲性能和阻尼性能主要由外侧纤维决定。次外层芳纶纤维在受压侧特殊的失效模式会加速最外层碳纤维的破坏。混杂复合材料的损耗因子同时受到混杂比和铺层结构的影响。混杂界面处的应力突变和泊松比不匹配对阻尼性能有增强作用。 基于对混杂复合材料结构与性能关系的研究，本章建立了实际载荷下混杂复合材料的阻尼预测方法。针对自制材料力学参数难以获取的问题，从力学性能参数较易获取的纤维和基体出发，首先得到了复合材料中织物的几何特征参数，建立织物复合材料的代表性体积单元，利用有限元法计算得到碳纤维复合材料和芳纶纤维复合材料的工程力学参数。随后本文将模态应变能法和模态叠加法相结合建立了实际载荷下混杂结构损耗因子的计算方法。利用此方法计算了多种碳芳混杂结构在1 Hz实际振动载荷下的损耗因子。模拟和试验结果的对比表明该方法具有一定的精确度。 关键词：阻尼；基体改性；界面摩擦；纤维界面增强；混杂复合材料

 Carbon fiber reinforced plastics (CFRP), the representative of advanced composites, have the advantages of high specific strength and modulus, which have been widely used in industry and equipment instead of traditional materials. Therefore, vibration and noise that perplex the traditional materials are also prominent in the application of composite materials. Vibration and noise can affect people’s working and living environment, reduce the performance and production efficiency of the system and destroy the stability and reliability of equipment. The long-term vibration may also cause damage to the structure, resulting in the decline of the effective life of the structure. The thin-walled components occupy a considerable proportion in composite. In the application fields of high-speed, the negative effects of vibration and noise will be more obvious. Therefore, the research of vibration and noise reduction of composite materials is of great significance. The vibration and noise reduction performance of composites depends on damping and modulus. The improvement of modulus can ameliorate the performance of vibration and noise reduction at low frequencies, while damping can improve the performance of vibration and noise reduction of composite materials in the whole frequency domain. Therefore, both high damping and high stiffness are essential for the reduction vibration and noise for composite materials, and high stiffness is also an inevitable requirement for composite materials as structural materials. The research on the integration design of structural damping properties of composite structures is mainly focused on the “interlayer” structure, which originated from the traditional additional damping structure and the damping layer was directly inserted into the interlayer. The co-curing damping composites materials with rubber as damping layer showed the weakness of stiffness degradation, low interfacial bonding, poor heat resistance; while other non-rubber damping composites would increase the total thickness, quality and process cost. Composite materials have the advantages of multi-component, multiinterface and designability. The structural damping composites independent of intercalation structure can be designed by making full use of these characteristics. Therefore, this paper tried to get rid of the thinking of intercalation modification and the integrated design of damping structural composites was studied from the perspective of the basic structure on the premise of making fully sense of the source and mechanism of damping of fiber reinforced composites. In this paper, the matrix-based integration design of structurl damping properties was achieved by nanoparticles modification. Three representative nanoparticles were selected to study the effects on mechanical properties, damping and thermal properties of epoxy matrix. (1) MWCNT (Multi-Walled Carbon Nanotubes). MWCNT with different dimensions were dispersed into epoxy matrix by solvent-based high-speed shear method. The dispersion process of MWCNT was qualitatively analyzed by theoretical calculation, which played a guiding role in the improving of dispersion method. The results of Halpin-Tsai model and tensile test were compared to determine whether MWCNT was well dispersed in the matrix. The results indicated that the addition of MWCNT can synchronously enhance the mechanical properties and damping properties of epoxy matrix. The tensile modulus, tensile strength and loss factor of epoxy matrix was increased by 20%, 8%, and 56% (25℃ 1 Hz), respectively. MWCNT with large aspect ratio and specific surface area showed the most obvious enhancement effect on mechanical properties and damping properties. Agglomerations exhibited a negative impact on the mechanical properties and damping of the matrix. The influence of dimensions and agglomerations on T〓 were just contrary to that on the mechanical properties and damping properties. (2) g-C₃N₄. g-C₃N₄ was prepared by thermal polycondensation method by using urea as precursor, and a series of characterization tests were carried out. Then it was dispersed into epoxy matrix by highspeed shear as a novel filler. The tensile modulus and flexural modulus of the modified epoxy matrix were increased by 17.29% and 12.38%, respectively. T〓 was also increased by 4-5℃. The remarkable improvement in mechanical properties and T〓 was attributed to the strong interaction interfaces and the mechanical interlocking effect caused by the curly structure and the large specific surface area. The loss factor of the modified matrix increased from 0.035 to 0.049 (25℃ 1 Hz). The enhancement of damping may caused by the combination of interlayer sliding friction, periodic breakage and reconstruction of hydrogen bond, and the micro-mechanical constrained layer damping mechanism. The initial thermal decomposition temperature (T〓) and 50% thermal decomposition temperature (T〓) were both increased by 15℃. 3) CSR (Core-shell structure nano-rubber). CSR is a new epoxy toughening agent. In view of the close relationship between toughening and damping of matrix, nanocomposites were prepared by mixing CSR with epoxy matrix. The test results showed that the impact strength of the matrix increased from 22.33 ±4.77 KJ/㎡ to 36.89±4.43 KJ/㎡ by adding 10 wt% of CSR. The tensile and flexural properties decreased slightly and the T〓 almost unchanged, while the addition of CSR also had little effect on the damping enhancement. Finally, fiber reinforced composites were prepared by nanoparticle modified matrix with the best comprehensive properties. The test results indicated that MWCNT and g-C₃N₄ modified matrix can enhance the mechanical and damping properties of fiber reinforced composites. The interface-based integration design of structural damping composites was realized by implementing multi-scale nanoparticles into the surface of fiber. Based on the study of g-C₃N₄, carbon fibers loaded with g-C₃N₄ were synthesized in situ to improve the mechanical and damping properties of fiber reinforced composites. The roughness, functional groups and wettability on the carbon fiber surface were greatly improved by introducing g-C₃N₄ and the interfacial properties of composite laminates were also markedly enhanced. Interlaminar shear strength and interfacial shear strength of composite laminates were increased from 51.84 MPa to 72.09 MPa and 44.62 MPa to 73.41 MPa, respectively. Tensile strength and bending strength were increased by 19.54% and 10.51%, respectively. The total absorbed energy of impact experiment was also enhanced from 1.14 to 1.78 J. The T〓 was increased from 116.71 to 121.34℃. The loss factor of the modified fiber reinforced composites was 2.2 times as much as that of the unmodified ones, and the merit of the modified fiber reinforced composites was increased by 114.1 %. The fiber-based integration design of structural damping composites was achieved by introducing high-damping fibers into carbon fiber composites. The test results showed that the hybrid composites exhibited compromised mechanical and damping properties. The tensile modulus of hybrid composites was only determined by the hybrid ratio, while the tensile strength and failure behavior were affected by both the hybrid ratio and stacking sequence. The structure of continuous multi-layer carbon fibers in the center of hybrid structure can produce a positive hybrid effect on tensile strength. The flexural and damping properties of hybrid composites were mainly determined by the fibers of the outer layer. The special failure mode of aramid fibers in the secondary layer at the compression side accelerated the failure of carbon fibers in the outermost layer. The loss factors of hybrid composites were also affected by both hybrid ratio and stacking sequence. The abrupt of stress and mismatch of Poisson’s ratio at the hybrid interface can enhance the damping performance. Based on the study of the relationship between the structure and properties of hybrid composites, a method for predicting the damping of hybrid composites under actual loads was established in this chapter. In view of the difficulty in obtaining mechanical parameters of self-made materials, this paper started with the mechanical properties of fiber and matrix which were easily obtained, then the geometric parameters of the fabric in the composites were achieved by means of metallographic microscope and scanning electron micro-scope, and then the representative volume elements were established. The engineering mechanical parameters of CFRP and AFRP were calculated by the finite element method (FEM). Subsequently, the modal strain energy and modal superposition were combined to establish a method for calculating the loss factor under actual loads. The loss factors of kinds of carbon/aramid hybrid composites in 1 Hz were predicted. The comparing of simulations and experimental results indicated that the method possesses a good accuracy. Keyword: damping; matrix modification; interface enhancement; interface friction; hybrid composites