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1.
对玻璃纤维增强聚氨酯泡沫的微观结构形态及增强效果进行了研究。结果表明,纤维在体系内呈单根纤维,小束纤维及大束纤维等多种形态分布。单丝及小丝束可以成为泡沫结构的共同支柱而起增强作用,在小束丝附近出现密集泡孔,发生少量树脂积聚。  相似文献   

2.
复合材料干纤维缠绕增强结构可解决纤维缠绕树脂基复合材料结构耐冲击性差、低温环境树脂易失效等问题。干纤维增强结构缠绕过程中,纤维束重叠、压缩导致干纤维缠绕增强层各处厚度不一,会对缠绕线型稳定性产生影响。为满足缠绕线型稳定,研究了测地线干纤维缠绕增强层厚度变化及分布规律,分析了纱带宽度、极孔尺寸及芯模结构等参数对增强层厚度的影响,考虑芯模厚度的变化,逐层更新干纤维缠绕增强结构数学模型,进行了缠绕轨迹计算,获得测地线缠绕线型。缠绕实验表明:理论仿真获得的复合材料干纤维缠绕增强容器增强层厚度准确,缠绕线型稳定,无滑纱现象,验证了纤维厚度与缠绕轨迹计算方法的可行性和干纤维增强层厚度仿真的正确性。  相似文献   

3.
跨尺度预测非屈曲织物增强复合材料的刚度和强度   总被引:1,自引:0,他引:1       下载免费PDF全文
为了预测非屈曲织物增强复合材料的力学性能, 建立了纤维束的正六边形单胞和非屈曲织物复合材料的长方形单胞, 并重点推导了正六边单胞的方程边界条件。通过跨尺度逐级计算这两个单胞的有效弹性常数, 得到了非屈曲碳纤维织物增强环氧树脂基复合材料的宏观有效弹性性能和强度。对该非屈曲织物复合材料在拉伸载荷下的累计失效进行了有限元损伤分析。结果表明: 初始损伤发生在富树脂区或横向纤维束, 损伤在富树脂区与横向纤维束内逐步扩展, 最后向纵向纤维束扩展并迅速导致整体失效; 非屈曲织物增强复合材料的面内拉伸模量的计算预测值非常接近实验值, 面内拉伸强度计算值略小于实验值。  相似文献   

4.
为研究纳米纤维增强闭孔泡沫材料的力学性能,采用Voronoi随机泡沫模型对闭孔泡沫材料的细观几何结构进行模拟,并将纳米纤维随机分布在泡沫材料的胞壁中,利用改进的自动搜索耦合(ASC)技术将纤维单元与基体单元进行耦合,建立了能够反映纳米纤维增强闭孔泡沫材料细观结构的数值模型。在此基础上,进一步研究了泡沫模型随机度、相对密度以及纳米纤维长径比和质量分数对纳米纤维增强闭孔泡沫材料弹性模量与屈服强度的影响规律。结果表明:由所建立的数值模型得到的纳米纤维增强闭孔泡沫材料的弹性模量和屈服强度与实验值吻合较好;提高泡沫模型的随机度会使复合泡沫材料的弹性模量和屈服强度增加,而当随机度达到0.450以后,材料的弹性模量和屈服强度几乎不再发生变化;当相对密度在0.05~0.30范围内变化时,复合泡沫材料的弹性模量与屈服强度几乎随相对密度的增加呈线性增长;提高纳米纤维长径比和质量分数也会使材料的弹性模量和屈服强度得到提高,但当纤维长径比达到500以后,纤维长径比的增强作用逐渐减弱。所得结论对纳米纤维增强闭孔泡沫材料的制备具有重要意义。  相似文献   

5.
通过研究增强纤维对环氧树脂的电子束辐射固化区域增长形貌及固化度梯度变化的影响发现:未经处理的碳纤维与树脂混合体系经辐射固化后,在纤维根部存在明显空隙。碳纤维经过硝酸处理后,树脂与纤维间的界面结合明显改善。加入增强纤维后,树脂体系的辐射固化层厚度和凝胶含量均有所下降,其下降幅度随纤维含量增加而变大,碳纤维的影响作用大于玻璃纤维。与纯树脂体系相比,纤维树脂混合体系在靠近电子束辐射表面处的凝胶含量随辐射深度增加现象不明显。  相似文献   

6.
增强硬质聚氨酯泡沫的研究进展   总被引:1,自引:1,他引:1  
根据增强材料的特性和增强方式把增强硬质聚氨酯泡沫分为纤维增强、微粒增强、聚合物合金(互穿聚合物网络)、复合增强等4类,主要介绍近年来不同种类增强硬质聚氨酯泡沫的力学性能、形态结构和增强机理等方面的研究进展,并展望增强硬质聚氨酯泡沫的发展趋势.  相似文献   

7.
Z-pin增强对泡沫夹层结构弯曲和振动性能的影响   总被引:2,自引:1,他引:1  
通过试验研究了Z-pin增强泡沫夹层结构的弯曲性能,与未增强材料进行比较.提出采用树脂Z-pin对泡沫夹层结构进行横向增强,比较了碳pin和树脂pin的不同增强效果.结果表明,横向增强能够极大地改善泡沫夹层结构的弯曲性能,树脂pin的增强作用虽然弱于碳pin,但同样具有明显的增强效果.在此基础上,基于Z-pin增强泡沫夹芯的力学性能,对夹层结构的弯曲刚度和弯曲最大破坏载荷进行预测.最后考察了增强Z-pin各参数对泡沫夹层结构自振频率的影响,为其在航空航天等振动结构中通过合理的阻尼设计达到调频的目的打下基础.  相似文献   

8.
综合原料的热物理性能分析和配比设计,实现了C/C复合材料载体孔隙体积的精细控制,采用热压-熔渗两步法在低温条件下制备了具有高致密、低残余Si含量特征的短碳纤维增强C/C-SiC复合材料。系统解析了C/C-SiC复合材料成型过程中的结构演变行为,研究了短纤维增强C/C-SiC复合材料的力学性能和失效机制。结果表明:多孔C/C复合材料载体孔隙的孔径呈双极分布特征,添加芳纶纤维可提高网络孔隙结构的连通性,具有显著的孔隙结构调控作用。SiC基体以网络骨架形态分布于C/C-SiC复合材料内部,与纤维束形成了强界面结合钉扎结构,高含量纤维协同作用下使C/C-SiC复合材料具有优异的综合力学性能,添加芳纶纤维可明显增加复合材料内部裂纹扩展路径,提高C/C-SiC复合材料的断裂韧性。碳纤维的面内各向同性分布及陶瓷相层间均匀分布对C/C-SiC复合材料承载、摩擦稳定性提升均具有积极作用。  相似文献   

9.
连续纤维增强PPESK树脂基复合材料的界面性能   总被引:6,自引:0,他引:6  
陈平  陆春  于祺  孙明 《材料研究学报》2005,19(2):159-164
用SEM观察了复合材料的微观断面结构,用横向拉伸强度和层间剪切强度表征玻璃纤维(GF)、T700碳纤维(CF)、芳纶纤维(F-12)增强PPESK树脂基复合材料的界面性能,研究了界面性能对三种复合材料耐湿热性能的影响.结果表明,T700/PPESK和F-12/PPESK复合材料的界面粘接性能均优于GF/PPESK复合体系.三种纤维复合材料的破坏机理不同:玻璃纤维发生纤维与树脂的界面脱粘破坏,碳纤维复合材料在破坏时,树脂与纤维并没有完全脱粘,破坏发生在树脂内;而芳纶纤维复合材料的破坏总伴随着纤维本身横向的撕裂破坏.三种复合材料体系均具有较低的吸湿率和良好的耐湿热性能,T700/PPESK复合材料在湿热条件下的性能保持率最高.  相似文献   

10.
聚苯硫醚及其纤维增强复合材料的等温结晶形态   总被引:1,自引:0,他引:1       下载免费PDF全文
采用热台偏光显微镜技术观察了聚苯硫醚(PPS)及其玻璃纤维、 炭纤维及芳纶纤维增强复合材料等温结晶过程中球晶结构形态的变化。研究了等温结晶温度对PPS的晶体形态及球晶生长速率的影响。结果表明, 结晶温度对PPS的结晶影响非常明显。在235~265℃, 随着等温结晶温度的升高, 聚苯硫醚球晶形态发生了从细小而具有部分束状结构到大而完善再到细小而不完善的变化过程, 球晶的生长速率随着结晶温度的增大呈非线性下降。而纤维的存在使PPS的结晶形态发生了从球晶结构到横穿晶的变化, 且不同纤维诱导形成横穿晶的程度有所不同。其中玻璃纤维和芳纶纤维可以诱导形成较为明显的横穿晶形态, 而炭纤维则不能诱导形成明显的横穿晶。  相似文献   

11.
研究了用短切玻璃纤维对硬质聚氨酯泡沫体的增强效果及拉伸、压缩的破坏行为。结果表明当纤维长为12 mm 时, 6 w t% 纤维含量的增强效果为最好, 可以使泡沫体的拉伸强度提高75% , 压缩强度提高25% , 压缩模量增加约30%。纤维增强的泡沫体拉伸产生的裂纹扩展时, 遇到纤维可能终止扩展(应力不大时) , 也可能发生偏转(应力较大时) ; 泡沫破坏时, 可能出现纤维拉出、拉断等不同的破坏形式。增强泡沫体在压缩破坏时, 主要是泡沫结构的支柱弯曲、扭转变形引起泡壁破裂和支柱失稳, 并导致材料的破坏。  相似文献   

12.
The mechanical properties at transverse deflection, bending and impact tests were examined in three fibre reinforced resins including reinforcing materials such as inorganic glass fibre and cloth, organic Kevlar fibre and combined fibres. Both heat-cured and microwave-cured reinforced materials had almost the similar pattern to the changes in the mechanical properties, as compared with those in visible light-cured reinforced resin. Their reinforcing materials increased modulus and impact energy by about two times as compared with the bases. The visible light-cured resin was, however, not effective as a base resin when reinforced with fibres tested here, indicating that the transverse deflection and modulus values in light-cured reinforced resin were similar to that in the plain base resin.  相似文献   

13.
Mechanical properties of natural fibre reinforced polymer composites   总被引:1,自引:0,他引:1  
During the last few years, natural fibres have received much more attention than ever before from the research community all over the world. These natural fibres offer a number of advantages over traditional synthetic fibres. In the present communication, a study on the synthesis and mechanical properties of new series of green composites involving Hibiscus sabdariffa fibre as a reinforcing material in urea-formaldehyde (UF) resin based polymer matrix has been reported. Static mechanical properties of randomly oriented intimately mixed Hibiscus sabdariffa fibre reinforced polymer composites such as tensile, compressive and wear properties were investigated as a function of fibre loading. Initially urea-formaldehyde resin prepared was subjected to evaluation of its optimum mechanical properties. Then reinforcing of the resin with Hibiscus sabdariffa fibre was accomplished in three different forms: particle size, short fibre and long fibre by employing optimized resin. Present work reveals that mechanical properties such as tensile strength, compressive strength and wear resistance etc of the urea-formaldehyde resin increases to considerable extent when reinforced with the fibre. Thermal (TGA/DTA/DTG) and morphological studies (SEM) of the resin and biocomposites have also been carried out.  相似文献   

14.
树脂基纤维增强摩阻材料研究进展   总被引:10,自引:1,他引:10  
综述了国内外目前树脂基纤维增强摩阻材料的研究进展,主要介绍了树脂基摩阻材料的摩擦学特性及摩擦磨损机理;树脂基体的改性研究成果,归纳了填料种类对摩阻材料摩擦学特性的影响.对常用的增强纤维性能作了对比,尤其是对天然植物剑麻纤维及其增强材料特性作了总结.笔者首次研究了剑麻纤维增强汽车刹车片,认为将剑麻纤维应用于摩阻材料将会是一个新的研究热点.  相似文献   

15.
A polymer fabric reinforced composite is a high performance material, which combines strength of the fibres with the flexibility and ductility of the matrix. For a better drapeability, the tows of fibres are interleaved, resulting the woven fabric, used as reinforcement. The complex geometric shape of the fabric is of paramount importance in establishing the deformability of the textile reinforced composite laminates. In this paper, an approach based on Classical Lamination Theory (CLT), combined with Finite Element Methods (FEM), using Failure Analysis and Internal Load Redistribution, is utilised, in order to compare the behaviour of the material under specific loads. The main goal is to analyse the deformability of certain types of textile reinforced composite laminates, using carbon fibre satin as reinforcement and epoxy resin as matrix. This is accomplished by studying the variation of the in-plane strains, given the fluctuation of several geometric parameters, namely the width of the reinforcing tow, the gap between two consecutive tows, the angle of laminae in a multi-layered configuration and the tows fibre volume fraction.  相似文献   

16.
The term “self-sensing composites” is sometimes used to describe the case where the reinforcing glass fibres in advanced fibre-reinforced composites are used as the sensors for chemical process-monitoring (cure monitoring). This paper presents conclusive evidence to demonstrate that reinforcing E-glass fibres can be used for in situ cure monitoring. The cure behaviour of an epoxy/amine resin system was compared using evanescent wave spectroscopy via the reinforcing E-glass fibres and conventional transmission Fourier transform infrared spectroscopy. This paper also reports for the first time that evanescent wave spectroscopy via E-glass fibres can be used to detect the presence of silane coupling agents. Preliminary results indicated that the cure kinetics on the E-glass fibre surface, as observed using evanescent wave spectroscopy, were influenced by the silane coupling agent.  相似文献   

17.
The tensile strength of epoxy resin reinforced with random-planar orientation of short carbon and glass fibres increased as the length of the reinforcing fibres increased, and the increase in tensile strength remained almost unchanged after the fibre length reached a certain level. The tensile strength of composites at any fibre length could be estimated by taking the strain rate and temperature dependence of both the yield shear strength at the fibre-matrix interphase and the mean critical fibre length into consideration. The tensile strength of the hybrid composite could be estimated by the additive rule of hybrid mixtures, using the tensile strength of both composites.  相似文献   

18.
Due to environmental awareness and economical considerations, natural fibre reinforced polymer composites seem to present a viable alternative to synthetic fibre reinforced polymer composites such as glass fibres. This is a feasibility study to asses the potential application of natural fibre reinforced sheet moulding compound materials (NF-SMC) for the use in building applications, with particular emphases to their reaction to fire. The reinforcing fibres in this study were industrial hemp fibres. The cone calorimeter which asses the fire hazard of materials by Heat Release Rate (HRR) was used, radiant heat fluxes of 25 and 50 kW/m2 were utilised to simulate an ignition source and fully developed room fire conditions respectively. The results acquired here demonstrate that the NF-SMC can compete with current building materials in terms of their fire behaviour. The peak heat release value for the fire retardant (FR) NF-SMC was 176 kW/m2 conversely for a non-FR NF-SMC was 361 kW/m2.  相似文献   

19.
The interlaminar shear strength of unidirectional ultra-high-modulus polyethylene composites was measured as a means of accessing the level of fibre/epoxy resin adhesion for a number of different reinforcing yarns, produced by melt and gel-spinning. The fibres were shown to possess poor adhesive properties due partly to inadequate wetting associated with the inert polyolefine surface and also because of a weak boundary layer, formed by the segregation of low molecular weight impurities to the surface during fibre formation. The interlaminar shear strength was significantly increased by pretreating the reinforcement with an oxygen plasma. This improved wetting by producing oxygen-containing groups on the fibre surface and removed the weak boundary layer by the formation of a cross-linked skin. For a fixed fibre volume fraction, the interlaminar shear strength was found to be inversely proportional to the filament diameter. The other mechanical properties were shown to be largely independent of fibre/resin adhesion, with plasma treatment having little or no effect.  相似文献   

20.
混杂增强聚氨酯复合硬泡塑料的物理及力学性能   总被引:8,自引:1,他引:7       下载免费PDF全文
研究纤维与颗粒混杂增强聚氨酯复合硬泡塑料的物理及力学性能,着重分析增强剂SiO2颗粒和玻璃纤维含量以及纤维长度对其性能的影响。结果表明,SiO2含量为20 wt%,玻璃纤维含量为7.8 wt%时,试样的拉伸强度达到最佳值。此外,还比较了玻璃纤维、尼龙66纤维和PAN基碳纤维的增强效果。结果表明,3 wt%~5 wt%含量碳纤维增强的聚氨酯复合硬泡塑料拉伸强度最佳。  相似文献   

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