共查询到20条相似文献,搜索用时 62 毫秒
1.
本文通过数值仿真计算出不同自紧压力下对气瓶疲劳寿命的影响规律,得到了铝合金内胆碳纤维缠绕气瓶最佳自紧压力。首先,构建了工作压力为35MPa的精细化有限元气瓶模型。其次,采用渐进损伤方法计算出复合材料铺层在自紧压力和疲劳循环压力下的基体损伤,从而得出了基体损伤后的气瓶内胆应力分布,建立了基于Morrow平均应力修正的Manson-Coffin等效应变法的气瓶疲劳寿命预测方法。根据纤维应力比计算出了自紧压力范围,并开展了不同自紧压力对气瓶疲劳寿命的影响规律研究。结果表明,在53MPa自紧压力之前,气瓶疲劳寿命随着自紧压力的增高稳定提升;在自紧压力达到53MPa之后,气瓶疲劳寿命变化波动较小,且在57MPa自紧压力下达到最大疲劳寿命之后出现下降趋势。因此,最终得出本文铝合金内胆碳纤维缠绕气瓶的最佳自紧压力为57MPa。 相似文献
2.
《玻璃钢/复合材料》2020,(6)
为了提高天然气汽车的续航里程,设计了30 MPa车用全缠绕压缩天然气气瓶。本文基于有限元软件平台下的复合材料分析模块,研究了不同的自紧压力对采用小角度螺旋缠绕、大角度螺旋缠绕加环向缠绕三种混合缠绕的全缠绕复合气瓶疲劳性能的影响,分析时采用SWT平均应力修正方程对交变应力幅进行了修正。结果表明:对气瓶进行自紧处理,基本不会改变内胆的交变应力幅,但是却可以降低其平均应力;在满足纤维应力比的前提下得出其最佳自紧压力为52 MPa,此时其疲劳循环次数约为15000次。 相似文献
3.
《玻璃钢/复合材料》2020,(1)
本文研究自紧压力对薄壁金属内衬复合材料气瓶性能的影响规律。采用有限元分析方法对气瓶的自紧过程进行数值模拟,缠绕成型复合材料气瓶,进行水压疲劳及爆破试验验证,并在试验过程中引入声发射监测。试验及分析结果表明,自紧压力对薄壁金属内衬复合材料气瓶的疲劳及爆破性能影响较大,自紧压力过大会使得气瓶复材层出现树脂开裂、纤维断裂等损伤,导致复合气瓶爆破强度值下降。疲劳试验结果表明,自紧压力过大容易导致薄壁内衬提前进入屈服状态,降低疲劳寿命。针对薄壁金属内衬复合材料气瓶,其自紧压力的选取必须充分考虑金属内衬在自紧及工作过程中的应力值,使其在合理区间。 相似文献
4.
5.
6.
7.
采用等效应变法计算气瓶疲劳寿命的ASME压力容器规范,不能考虑多轴非比例加载效应,具有明显的不足。针对复合材料气瓶,采用修正的Brown-Miller算法研究其多轴低周疲劳寿命,并分析了自紧压力、金属内衬厚度和单层缠绕层厚度对复合材料气瓶疲劳寿命的影响,给出了提高复合材料气瓶疲劳寿命的方法。 相似文献
8.
9.
为研制高结构效率的复合材料气瓶,采用T700碳纤维/环氧树脂体系在薄壁铝金属内衬上缠绕成型复合气瓶,对其进行了水压自紧试验,100次0~36MPa水压疲劳试验以及水压爆破试验,并且采用声发射、应变测试等方法对试验过程进行检测。结果表明,经过水压自紧试验后复合材料气瓶具有较好的疲劳性能,100次疲劳对气瓶的损伤较少,并且经过疲劳后的气瓶爆破压强仍然达到88MPa,具有较高的结构效率。 相似文献
10.
受气瓶用无缝钢管壁厚偏差影响,环缠绕复合气瓶内胆实际壁厚可能存在0~+30%的变化。内胆实际壁厚变化会影响复合气瓶的自紧效果,从而影响复合气瓶的抗疲劳性能。采用有限元方法对壁厚不同的钢质内胆玻璃纤维环缠绕复合气瓶进行了应力分析。结果表明,随着内胆壁厚增大,相同自紧压力下内胆预压缩应力减小,工作过程中内胆平均应力增大,这会减弱气瓶的抗疲劳性能;但内胆疲劳交变应力幅减小,这对气瓶的抗疲劳性能又有增强作用。因此,分别基于Goodman和SWT平均应力修正方程,对计算所得的平均应力和疲劳交变应力幅进行了等效处理,两种方法所得等效交变应力幅均随内胆壁厚增大而减小。这表明二者的共同作用对环缠绕复合材料气瓶的抗疲劳性能有小幅度的提高,内胆实际壁厚的增大不会降低环缠绕复合气瓶的抗疲劳性能。 相似文献
11.
12.
M. S. J. Simmonds W. M. Blaney F. Delle Monache M. Marquina Mac-Quhae G. B. Marini Bettolo 《Journal of chemical ecology》1985,11(12):1593-1599
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. 相似文献
13.
Cheng-Le Zhao Shane Porzio Alan Smith Haiyan Ge H. T. Davis L. E. Scriven 《Journal of Coatings Technology and Research》2006,3(2):109-115
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. 相似文献
14.
15.
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. 相似文献
16.
17.
18.
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. 相似文献
19.
中蓝晨光化工研究院《塑料工业》编辑部 《塑料工业》2007,35(3):1-25,67
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。 相似文献
20.
中蓝晨光化工研究院有限公司《塑料工业》编辑部 《塑料工业》2009,37(3)
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. 相似文献