复合材料多隔板框梁结构的RTM工艺成型

复合材料多隔板框梁结构复杂,内外形精度要求高,本文研究了采用树脂传递模塑成型(RTM)工艺实现该类结构的精确制造。介绍了RTM成型模具的设计、预制体的制备及其注胶工艺的改进,并讨论了它们对于RTM制件质量的影响。结果表明,整体线型注胶口利于大型复杂结构的树脂注胶;适当增大注胶压力,并进行保压,有利改善制件表面质量;控制预制体和树脂中的气泡有利改善制件内部质量;预制体转角区增加额外填充材料可以避免该区域的富树脂及其脱落引起的表面缺陷。最后对其力学性能进行了测试分析。     

小型无人机中机身复合材料成型技术研究

正小型无人机中机身为复合材料层压结构,外形主要为双曲型闭环腔体;零件由于体积小、翼身融合结构复杂而使得工艺成型难度较大,故主要从工艺成型角度对该结构进行了具体的研究与探讨。0前言复合材料因其独特的性能而广泛应用于各国的飞机制造中,并且从最初的次结构逐渐发展到现在的主承力复杂结构[1]。针对无人机特有的低风险(无人)、低成本(较大飞机而言)及总体尺寸较小等特点[2],利用复合材料的优良性能和各种工艺成     

赢创硬质泡沫应用于中国商用客机

赢创公司推出的ROHACELLPMI（聚甲基丙烯酰亚胺）硬质泡沫最近成功用于制造中国第一架大型商用客机C919的后压力框部段样件。在商用飞机中使用复合材料作为主承力结构,在国内尚属首次。后压力框部段样件是C919在研制过程中完成的第一个大型复合材料部段样件,     

超轻复合材料机翼结构设计及成型技术研究

在给定外形与尺寸的机翼设计要求下,进行了机翼结构设计、工艺设计、产品制造及力学性能实验研究。采用有限元分析软件,对复合材料机翼进行静力学分析,提取了主承力结构,设计了内部骨架结构。提出了"工字梁+薄蒙皮+变厚度"的结构方案,并通过碳纤维复合材料铺层设计和聚甲基丙烯酰亚胺(PMI)泡沫设计,实现机翼内部的结构制造。研究了复杂外形零件模具的设计思路,设计了中央翼盒和机翼双模具。采用模压+共胶接成型工艺方法,设计了机翼成型工艺流程。通过这种方法成功制造了机翼,并进行了力学性能测试。最终制备的机翼表面质量和外形尺寸满足要求,实现了重量轻、载荷比重大的机翼设计与制造。证明了本文结构设计及成型方法的合理性与有效性。     

复合材料风扇叶片钛合金加强边胶接技术研究

本文以航空发动机复合材料风扇叶片钛合金加强边胶接为研究背景,开展钛合金/复合材料胶接技术研究,着重研究了基于AF191胶膜的钛合金/复合材料胶接工艺参数、不同结构复合材料与钛合金以及不同表面处理方式钛合金与复合材料胶接强度。结果显示:采用热压罐固化,并且在加压0.1 MPa后卸掉真空更有助于胶接;不同结构复合材料对胶接强度影响较大,刚度更高的复合材料表现为更好的胶接强度;采用酸洗和阳极化处理钛合金表面均能大幅提高胶接强度,并且配合表面预处理剂使用更佳。     

1986-2006我国FRP/CM工业技术进步及行业发展(民品部分)

神舟飞船主承力结构、低密度模塑料等FRP件荣获国家科技进步二等奖，标志着我国复合材料科学技术已达到世界先进水平；历经20年，我国FRP／CM年产量已超过日本、欧洲，大幅度提升，显示了当今我国FRP行业的活力。     

厚截面复合材料结构固化残余应力研究进展

随着复合材料在飞机机架主承力构件的广泛应用,厚截面复合材料构件固化过程残余应力的预测和控制是必须解决的关键问题之一。厚截面复合材料的残余应力形成机制远较薄板复杂,更易发生温度过热、紧密压实不完全、非同步固化,固化残余应力大等问题。并且厚板在固化过程中形成的残余应力难以释放,降低复合材料结构的承载能力和使用寿命。采用数值模拟复合材料固化过程,优化固化工艺是是降低厚截面复合材料结构生产成本的有效方法。从热传导与化学反应、紧密压实和残余应力3个方面回顾了厚截面复合材料固化过程数值模拟的研究进展,对下一步的研究方向进行了展望。     

飞机复合材料阶梯式胶接结构的疲劳损伤与寿命

随着复合材料胶接技术在飞机主承力结构上的广泛应用,阶梯式胶接形式由于在实际工程过程中易于实现而成为复合材料结构修理和连接的主要形式。目前文献多集中于研究金属、复合材料以及两种材料混合的单搭接结构的疲劳性能,但对于具有高效载荷传递的阶梯式结构的疲劳耐久性研究较少,其疲劳失效机制尚需厘清。本文对多级阶梯复合材料胶接结构进行了拉伸疲劳试验研究,应力比为0. 1。在疲劳试验过程中观测了宏观裂纹的起始与扩展。根据试验数据拟合的S-N曲线,发现疲劳寿命随应力水平的增加而线性降低。在发现目视可见裂纹后至完全断裂,复合材料胶接结构仍具有10%的剩余寿命,说明当出现目视可见裂纹时,应及时维修或更换部件。从试样受力及破坏形式可知,复合材料胶接结构的剪切破坏是引起疲劳损伤的主要原因。通过阶梯状断口形貌分析,发现了内聚破坏、粘附破坏、基体开裂和分层四种典型破坏形式。     

Ni3Al/HAP生物复合材料的凝胶注模成形

采用凝胶注模成形工艺制备了Ni3Al／HAP生物复合材料,利用差热分析研究了复合材料坯体的排胶温度制度,经过力学性能测试Ni3Al／HAP生物复合材料及其坯体力学性能良好。     

车用高分子复合材料发展趋势及建议

从汽车内饰件、外部覆盖件和主承力结构件等不同性能要求的部件出发,综述了目前车用高分子复合材料的应用现状,系统分析了车用高分子复合材料在绿色环保、轻量化节能、低成本制造以及服役安全性等方面具有的优势和存在的不足,展望了其发展趋势。     

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.     

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.     

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。     

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.     

Inorganic/organic nanocomposite coatings: The next step in coating performance

Inorganic/organic hybrid materials have considerable promise and are beginning to become a major area of research for many coating usages, including abrasion and corrosion resistance. Our primary approach is to prepare the inorganic phase in situ within the film formation process of the organic phase. The inorganic phase is introduced via sol-gel chemistry into a thermosetting organic phase. By this method, the size, periodicity, spatial positioning, and density of the inorganic phase can be controlled. An important aspect of the inorganic/organic hybrid materials is the coupling agent. The initial task of the coupling agent is to provide uniform mixing of the oligomeric organic phase with the sol-gel precursors, which are otherwise immiscible. UV-curable inorganic/organic hybrid systems have the advantages of a rapid cure and the ability to be used on heat sensitive substrates such as molded plastics. Also, it is possible to have better control of the growth of the inorganic phase using UV curing. It is our ultimate goal to completely separate the curing of inorganic and organic phases to gain complete control over the morphology, and hence optimization of “all” the coating properties. Thus far, it has been found that concomitant UV curing of the inorganic and organic phases using titanium sol-gel precursors afforded nanocomposite coatings which completely block the substrate from UV light while maintaining a transparent to visible light. Also, it has been found that the morphology of the inorganic phase is highly dependent on the concentration and reactivity of the coupling agent. Presented at the 82nd Annual Meeting of the Federation of Societies for Coatings Technology, October 27–29, 2004, in Chicago, IL.     

Ethanol and (−)-α-Pinene: Attractant Kairomones for Some Large Wood-Boring Beetles in Southeastern USA

Ethanol and α-pinene were tested as attractants for large wood-boring pine beetles in Alabama, Florida, Georgia, North Carolina, and South Carolina in 2002–2004. Multiple-funnel traps baited with (−)-α-pinene (released at about 2 g/d at 25–28°C) were attractive to the following Cerambycidae: Acanthocinus nodosus, A. obsoletus, Arhopalus rusticus nubilus, Asemum striatum, Monochamus titillator, Prionus pocularis, Xylotrechus integer, and X. sagittatus sagittatus. Buprestis lineata (Buprestidae), Alaus myops (Elateridae), and Hylobius pales and Pachylobius picivorus (Curculionidae) were also attracted to traps baited with (−)-α-pinene. In many locations, ethanol synergized attraction of the cerambycids Acanthocinus nodosus, A. obsoletus, Arhopalus r. nubilus, Monochamus titillator, and Xylotrechus s. sagittatus (but not Asemum striatum, Prionus pocularis, or Xylotrechus integer) to traps baited with (−)-α-pinene. Similarly, attraction of Alaus myops, Hylobius pales, and Pachylobius picivorus (but not Buprestis lineata) to traps baited with (−)-α-pinene was synergized by ethanol. These results provide support for the use of traps baited with ethanol and (−)-α-pinene to detect and monitor common large wood-boring beetles from the southeastern region of the USA at ports-of-entry in other countries, as well as forested areas in the USA.