碳纤维复合材料在飞机结构中的应用

回顾了40年来碳纤维复合材料在飞机结构中的应用发展过程,从成本角度分析了影响其在飞机结构中扩大应用的障碍和现状,指出以碳纤维复合材料在空客A380、A350和波音787飞机中的大范围应用为代表,碳纤维复合材料技术已克服了成本障碍,为今后在更多领域高性能结构的大范围应用提供了可能,进入了大规模工业应用的新纪元。根据飞机结构使用碳纤维复合材料的经验教训,针对国内碳纤维发展现状,指出为扩大国产碳纤维在飞机及其他高性能结构中的应用,碳纤维生产企业应努力的方向:首先是保证产品质量的稳定性和可靠性,制订符合国际规范的材料标准和验收方法;其二应注重对碳纤维下游产品,即复合材料及其结构研制与评定,碳纤维是否能用于飞机结构,其主要依据是碳纤维对复合材料结构制造的适用性和相应的性能指标;同时应注意对复合材料结构设计技术的普及和人才培养。最后根据飞机结构完整性的要求,提出了对第二代碳纤维力学性能指标的某些建议。     

低成本碳纤维的研究进展与应用

碳纤维具有优异的力学性能，因此碳纤维及其复合材料在越来越多的行业中得到应用。然而，受限于碳纤维较高的制造成本，限制了碳纤维在风电、汽车、建筑增强材料等领域的规模化应用。近年来，世界多国对低成本碳纤维的研究付出了很多努力。碳纤维原丝制造成本是影响碳纤维制造成本的主要因素，这是目前低成本碳纤维的主要研究方向。综述了采用降低碳纤维原丝制造成本，进而降低碳纤维制造成本相关技术的研究进展，并对低成本碳纤维的应用领域现状进行了总结。     

碳纤维增强碳化硅基复合材料的研究

碳纤维增强碳化硅基复合材料(Cf/SiC)具有良好的力学性能,作为特殊结构的功能材料,是航空航天领域和新能源领域的研究热点之一。本文主要阐述了增强相碳纤维的发展,复合材料的基体复合技术,以及复合材料界面相的研究,并展望了碳纤维复合材料在高新技术领域中的应用与发展前景。     

碳纤维/聚氨酯复合材料的制备与性能研究

以聚酯二元醇、异氰酸酯、碳纤维为主要原料,采用预聚体法制备了一系列碳纤维/聚氨酯复合材料,并对该复合材料进行了性能测试和结构表征。研究表明,复合材料的机械性能随着碳纤维长度和含量的增加出现先升高后降低的趋势。当碳纤维长度为3 mm、质量分数为1.0%时,复合材料的机械性能达到最佳值,此时其拉伸强度增加22.7%,撕裂强度增加48.1%,扯断伸长率增加5.9%。热力学分析和动态力学性能研究表明,复合材料的热分解温度提高,质量保留率提高,失重率降低,材料的玻璃化转变温度和软化温度提高,引入碳纤维后材料的耐热性提高。     

碳纤维复合材料轨道车辆结构的设计分析

车体的轻量化是轨道交通车辆未来发展的方向之一,碳纤维复合材料是车体轻量化设计的优选材料。本文介绍了一种全碳纤维复合材料车体的轻量化设计,包括整车结构设计和连接设计。通过有限元方法对复合材料整车结构的强度、刚度以及模态进行了校核。进一步对碳纤维复合材料的力学性能进行了评价。并按照一体化成型和模块化的思维,采用真空辅助成型工艺在烘箱环境下制备复合材料车体试验段,验证了车体的结构设计和制造技术的可行性。研究结果表明:(1)碳纤维复合材料车体的设计应综合考虑材料特性、车体结构和承载方式,减少零部件数量和连接,实现车体的一体化成型;(2)碳纤维复合材料在车体制造上能够较大幅度减少车体质量。本文设计的碳纤维复合材料车体在满足车体强度、刚度和模态标准的前提下,全碳纤维复合材料车体相比传统铝合金车体减重42%。     

碳纤维复合材料引擎盖的轻量化设计

以汽车碳纤维复合材料引擎盖为研究对象，采用碳纤维复合材料为研究材料，以层合板理论为力学数值模拟CAE设计基础，利用ABAQUS软件对单层级试样准静态拉伸试验和典型U形梁结构准静态三点弯试验进行仿真，然后进行了台架模态和抗凹刚度测试。采用概念设计、材料性能试验和工艺设计多阶段联合优化设计的方法，最终在满足各种力学性能和制造工艺要求的前提下，实现碳纤维复合材料引擎盖的轻量化设计。     

碳纤维复合材料埋件在蜂窝夹层结构中的应用

本文以“嫦娥五号”月球探测器支撑结构和整形连接结构产品研制任务为背景,阐述了碳纤维复合材料埋件在蜂窝夹层结构中的成功应用,成功达到减重目标。本文介绍了在蜂窝夹层结构中采用碳纤维复合材料埋件代替铝合金埋件的应用过程,首先采用三维机织-RTM工艺和缝合-RTM工艺制造碳纤维复合材料坯件,进而通过机械加工手段制备相应埋件,为满足使用需求,在埋件内部安装相应的钢丝螺套。进一步对碳纤维复合材料埋件进行了力学性能和使用性能的试验验证,实现了碳纤维复合材料埋件在“嫦娥五号”月球探测器支撑结构和整形连接结构上的成功应用,满足结构力学和功能的需求,并达到结构减重和减小热变形的效果,值得推广应用。     

可大规模生产的生物基纤维塑料复合材料研发成功

<正>最近,德国开姆尼斯工业大学的研究人员开发出了一系列能够大规模生产的生物基纤维塑料复合材料,这种材料可以作为玻璃和碳纤维增强塑料的替代品。轻量级结构研究所研究员Ahmed-Amine Ouali表示:"我们用亚麻等天然纤维来替代玻璃纤维或碳纤维,并且我们的塑料基质是可再生的生物聚合物。因此,产品的生命周期中,碳足迹明显更好。"研究人员还说,使用连续的长丝可使复合材料在纤维方向     

碳纤维导电纸及其复合材料的开发与应用

介绍了碳纤维导电纸的制造方法,分析了影响其导电性能的因素,综述了碳纤维导电纸及其复合材料的应用.研究表明:碳纤维的长度、表面处理、质量分数、填料等是影响碳纤维导电纸导电性能的主要因素,碳纤维导电纸及其复合材料可在防静电和屏蔽、面状发热、耐热阻燃、燃料电池、高保真扬声器、生物医用等材料领域广泛应用.     

碳纤维填充聚四氟乙烯复合材料力学性能研究

聚四氟乙烯由于其优良的耐腐蚀性,作为换热设备材料逐渐被人们重视,但是由于聚四氟乙烯本身的力学性能不佳,限制了其大规模应用。为了改善聚四氟乙烯本身的力学性能,考虑以聚四氟乙烯为基体材料添加力学性能优良的碳纤维,首先用理论公式计算添加不同比例的碳纤维后复合材料力学性能的指标,其次采用ANSYS有限元数值模拟方法,模拟了不同进口流速对改性前和改性后的PTFE材料板翅式换热器压力和速度的影响,并进行分析,所得的结论对优化聚四氟乙烯复合材料力学性能有一定的价值。     

Insect antifeedant properties of anthranoids from the genusVismia

Vismiones and ferruginins, representatives of a new class of lypophilic anthranoids from the genusVismia were found to inhibit feeding in larvae of species ofSpodoptera, Heliothis, and inLocusta migratoria.     

Direct observation of freeze-thaw instability of latex coatings via high pressure freezing and cryogenic SEM

Despite its industrial importance, the subject of freeze-thaw (F/T) stability of latex coatings has not been studied extensively. There is also a lack of fundamental understanding about the process and the mechanisms through which a coating becomes destabilized. High pressure (2100 bar) freezing fixes the state of water-suspended particles of polymer binder and inorganic pigments without the growth of ice crystals during freezing that produce artifacts in direct imaging scanning electron microscopy (SEM) of fracture surfaces of frozen coatings. We show that by incorporating copolymerizable functional monomers, it is possible to achieve F/T stability in polymer latexes and in low-VOC paints, as judged by the microstructures revealed by the cryogenic SEM technique. Particle coalescence as well as pigment segregation in F/T unstable systems are visualized. In order to achieve F/T stability in paints, latex particles must not flocculate and should provide protection to inorganic pigment and extender particles. Because of the unique capabilities of the cryogenic SEM, we are able to separate the effects of freezing and thawing, and study the influence of the rate of freezing and thawing on F/T stability. Destabilization can be caused by either freezing or thawing. A slow freezing process is more detrimental to F/T stability than a fast freezing process; the latter actually preserves suspension stability during freezing. Presented at the 82nd Annual Meeting of the Federation of Societies for Coatings Technology, October 27–29, 2004 in Chicago, IL. Tied for first place in The John A. Gordon Best Paper Competition.     

Ethanol and (−)-α-Pinene: Attractant Kairomones for Bark and Ambrosia Beetles in the Southeastern US

In 2002–2004, we examined the flight responses of 49 species of native and exotic bark and ambrosia beetles (Coleoptera: Scolytidae and Platypodidae) to traps baited with ethanol and/or (−)-α-pinene in the southeastern US. Eight field trials were conducted in mature pine stands in Alabama, Florida, Georgia, North Carolina, and South Carolina. Funnel traps baited with ethanol lures (release rate, about 0.6 g/day at 25–28°C) were attractive to ten species of ambrosia beetles (Ambrosiodmus tachygraphus, Anisandrus sayi, Dryoxylon onoharaensum, Monarthrum mali, Xyleborinus saxesenii, Xyleborus affinis, Xyleborus ferrugineus, Xylosandrus compactus, Xylosandrus crassiusculus, and Xylosandrus germanus) and two species of bark beetles (Cryptocarenus heveae and Hypothenemus sp.). Traps baited with (−)-α-pinene lures (release rate, 2–6 g/day at 25–28°C) were attractive to five bark beetle species (Dendroctonus terebrans, Hylastes porculus, Hylastes salebrosus, Hylastes tenuis, and Ips grandicollis) and one platypodid ambrosia beetle species (Myoplatypus flavicornis). Ethanol enhanced responses of some species (Xyleborus pubescens, H. porculus, H. salebrosus, H. tenuis, and Pityophthorus cariniceps) to traps baited with (−)-α-pinene in some locations. (−)-α-Pinene interrupted the response of some ambrosia beetle species to traps baited with ethanol, but only the response of D. onoharaensum was interrupted consistently at most locations. Of 23 species of ambrosia beetles captured in our field trials, nine were exotic and accounted for 70–97% of total catches of ambrosia beetles. Our results provide support for the continued use of separate traps baited with ethanol alone and ethanol with (−)-α-pinene to detect and monitor common bark and ambrosia beetles from the southeastern region of the US.     

Methyl 2,4,6-decatrienoates Attract Stink Bugs and Tachinid Parasitoids

Halyomorpha halys (Stål) (Pentatomidae), called the brown marmorated stink bug (BMSB), is a newly invasive species in the eastern USA that is rapidly spreading from the original point of establishment in Allentown, PA. In its native range, the BMSB is reportedly attracted to methyl (E,E,Z)-2,4,6-decatrienoate, the male-produced pheromone of another pentatomid common in eastern Asia, Plautia stali Scott. In North America, Thyanta spp. are the only pentatomids known to produce methyl 2,4,6-decatrienoate [the (E,Z,Z)-isomer] as part of their pheromones. Methyl 2,4,6-decatrienoates were field-tested in Maryland to monitor the spread of the BMSB and to explore the possibility that Thyanta spp. are an alternate host for parasitic tachinid flies that use stink bug pheromones as host-finding kairomones. Here we report the first captures of adult and nymph BMSBs in traps baited with methyl (E,E,Z)-2,4,6-decatrienoate in central Maryland and present data verifying that the tachinid, Euclytia flava (Townsend), exploits methyl (E,Z,Z)-2,4,6-decatrienoate as a kairomone. We also report the unexpected finding that various isomers of methyl 2,4,6-decatrienoate attract Acrosternum hilare (Say), although this bug apparently does not produce methyl decatrienoates. Other stink bugs and tachinids native to North America were also attracted to methyl 2,4,6-decatrienoates. These data indicate there are Heteroptera in North America in addition to Thyanta spp. that probably use methyl 2,4,6-decatrienoates as pheromones. The evidence that some pentatomids exploit the pheromones of other true bugs as kairomones to find food or to congregate as a passive defense against tachinid parasitism is discussed.     

2007～2008年世界塑料工业进展

收集了2007年7月～2008年6月世界塑料工业的相关资料,介绍了2007～2008年国外塑料工业的发展情况,提供了世界塑料产量、消费量及全球各类树脂的需求量及产能情况.按通用热塑性树脂(聚乙烯、聚丙烯、聚苯乙烯、聚氯乙烯、ABS树脂)、工程塑料(尼龙、聚碳酸酯、聚甲醛、热塑性聚酯、聚苯醚)、特种工程塑料(聚苯·硫醚、液晶聚合物、聚醚醚酮)、通用热固性树脂(酚醛、聚氨酯、不饱和聚酯树脂、环氧树脂)不同品种的顺序,对树脂的产量、消费量、供需状况及合成工艺、产品应用开发、树脂品种的延伸及应用的进一步扩展等技术作了详细介绍.     

2005～2006年国外塑料工业进展

收集了2005年7月～2006年6月国外塑料工业的相关资料,介绍了2005—2006年国外塑料工业的发展情况。提供了世界塑料产量、消费量及全球各类树脂生产量以及各国塑料制品的进出口情况。作为对比,介绍了中国塑料的生产情况。按通用热塑性树脂（聚乙烯、聚丙烯、聚苯乙烯、聚氯乙烯、ABS树脂）、工程塑料（聚酰胺、聚碳酸酯、聚甲醛、热塑性聚酯、聚苯醚）、通用热固性树脂（酚醛、聚氨酯、不饱和树脂、环氧树脂）、特种工程塑料（聚苯硫醚、液晶聚合物、聚醚醚酮）的品种顺序,对树脂的产量、消费量、供需状况及合成工艺、产品开发、树脂品种的延伸及应用的扩展作了详细的介绍。