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ID:43710388
大小:2.50 MB
页数:97页
时间:2019-10-13
《pan基吸波纤维和吸波结构的研究》由会员上传分享,免费在线阅读,更多相关内容在工程资料-天天文库。
1、国防科学技术大学研究生院学位论文本文研究了聚丙烯騰(PAN)基吸波纤维和吸波结构的制备和性能,通过优化设计制备了性能较好的吸波结构。PAN预氧纤维在550C、600・C、650C进行了热处理,制备了3种吸波纤维。随着热处理温度的升高,纤维的介电常数增大。经过650C热处理的纤维,介电损耗角接近于1,在2GHz~18GHz频率范围内具有较好的频响特性。热处理气氛中影响最大的是水,减少热处理过程中的水分可以使制得的纤维电磁性能更稳疋。(用石蜡和吸波纤维制备了3种不同纤维体积分数的复合材料,测试了介电常数,经研究表明,复合材料的介电常数满足经验公式叫£:+勺
2、£匚对于介电常数实部,n=0.936,对于介电常数虚部,11=4.506°用手糊和模压工艺制备了纤维布/树脂复合材料,测试了电磁参数,建立了纤维布层板模型,确定了模型中纤维布层的等效厚度,手糊工艺成型为0.65mm,模压成型为056mmo对短切纤维吸波涂层进行了优化设计,2mm厚的吸波涂层反射率小于・10dB的带宽可以达到6GHzo用手糊和模压的王艺制备了6块纤维布吸波材料,测试了反射率,应用纤维布层板模型对材料的反射率进行了模拟计算,并且与实测值进行了比较,结果表明,两者吻合得较好。对纤维布吸波材料进行了优化设计,簣果表明,模压和手糊的吸波结构层数以
3、4层为宜,手糊制品厚度5.2mm,反射率小于-10dB的带宽为9.2GHz,模压制品厚度3・2mm,反射率小于-10dB的带宽为106血丿才~Ilf测试了所制得的吸波结构的力学性能,手糊制品弯曲强度为77MPa,弯曲国防科学技术大学研究生院学位论文abstractTheperformanceandpreparationofplyacylonitrile(PAN)basemicrowav4、hgoodperformancewasmadeafteroptimizationdesign.PANpreoxidizedfiberwasheat-treatedat550*C5600°Cand650'Ctoobtaumicrowaveabsorbingfibers.Whentheheat-treatmenttemperatureisincreased,th5、'C,thetangentofdielectriclossangleofthefibeapproachsto1,andthefrequencyresponsecharacteristicisfinefrom2GHzh18GHz.Intheheat-treatmentambience,thevaporisthemostimportantfactor,an(reducingthevaporcanmaketheelectromagneticpropertiesmoresteady-3kindsofcompositeswithdifferentfibervol6、umefractionweremadewitlparaffinandmicrowaveabsorbingshortcutfiber,andtheirdielectricconstantswenmeasured.Researchshowsthatthedielectricconstantsfitempiricalformula•Fortherealpartofdielectricconstants,nis0.936,andforth(imaginarypart,nis1.506.Themicrowaveabsobingfebric/resincompos7、itematerialsweremadewithhan(laying-upormouldpressing,andtheirdielectricconstantsweremeasured.Fabricmulti-layermodelwascreated,andequivalentthicknessoffabriclayerinthismodewasworkedout.Forhandlaying*uptheequivalentthicknesswas0.65mm,andfbmouldpressingtheequivalentthicknesswas0.568、mm.Theshortcutfibercoatwasoptimizationdesigned.
4、hgoodperformancewasmadeafteroptimizationdesign.PANpreoxidizedfiberwasheat-treatedat550*C5600°Cand650'Ctoobtaumicrowaveabsorbingfibers.Whentheheat-treatmenttemperatureisincreased,th5、'C,thetangentofdielectriclossangleofthefibeapproachsto1,andthefrequencyresponsecharacteristicisfinefrom2GHzh18GHz.Intheheat-treatmentambience,thevaporisthemostimportantfactor,an(reducingthevaporcanmaketheelectromagneticpropertiesmoresteady-3kindsofcompositeswithdifferentfibervol6、umefractionweremadewitlparaffinandmicrowaveabsorbingshortcutfiber,andtheirdielectricconstantswenmeasured.Researchshowsthatthedielectricconstantsfitempiricalformula•Fortherealpartofdielectricconstants,nis0.936,andforth(imaginarypart,nis1.506.Themicrowaveabsobingfebric/resincompos7、itematerialsweremadewithhan(laying-upormouldpressing,andtheirdielectricconstantsweremeasured.Fabricmulti-layermodelwascreated,andequivalentthicknessoffabriclayerinthismodewasworkedout.Forhandlaying*uptheequivalentthicknesswas0.65mm,andfbmouldpressingtheequivalentthicknesswas0.568、mm.Theshortcutfibercoatwasoptimizationdesigned.
5、'C,thetangentofdielectriclossangleofthefibeapproachsto1,andthefrequencyresponsecharacteristicisfinefrom2GHzh18GHz.Intheheat-treatmentambience,thevaporisthemostimportantfactor,an(reducingthevaporcanmaketheelectromagneticpropertiesmoresteady-3kindsofcompositeswithdifferentfibervol
6、umefractionweremadewitlparaffinandmicrowaveabsorbingshortcutfiber,andtheirdielectricconstantswenmeasured.Researchshowsthatthedielectricconstantsfitempiricalformula•Fortherealpartofdielectricconstants,nis0.936,andforth(imaginarypart,nis1.506.Themicrowaveabsobingfebric/resincompos
7、itematerialsweremadewithhan(laying-upormouldpressing,andtheirdielectricconstantsweremeasured.Fabricmulti-layermodelwascreated,andequivalentthicknessoffabriclayerinthismodewasworkedout.Forhandlaying*uptheequivalentthicknesswas0.65mm,andfbmouldpressingtheequivalentthicknesswas0.56
8、mm.Theshortcutfibercoatwasoptimizationdesigned.
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