Z-pin增强K-Cor泡沫夹层及其强化机制  

Z-pins reinforced K-Cor foam sandwich structure and its strengthening mechanism

作　　者：郑莹莹 肖军[2] ZHENG Yingying;XIAO Jun(Department of Aeronautical Engineering,Jiangsu Aviation Technical College,Zhenjiang 212134,Jiangsu,China;College of Materials Science and Technology,Nanjing University of Aeronautics and Astronautics,Nanjing 210016,China)

机构地区：[1]江苏航空职业技术学院航空工程系,江苏镇江212134 [2]南京航空航天大学材料科学与技术学院,南京210016

出　　处：《航空材料学报》2021年第6期89-97,共9页Journal of Aeronautical Materials

基　　金：2021年度院级课题资助项目(JATC21010111);军品配套项目(JTTP-1146)。

摘　　要：半固化Z-pin作为泡沫夹层的Z向增强棒,可获得质轻高强的泡沫夹层,被广泛应用于航天器外壳,以实现局部高承载和抗高空电磁辐射。本研究设计出一种新型K-Cor泡沫夹层结构,探讨不同固化度的Z-pin对泡沫夹层的增强机理。采用NHZP-1型双马树脂拉挤成型半固化态Z-pin,将Z-pin植入Rohacell-51WF泡沫基芯,遴选5429/HT7双马单向预浸料作为蒙皮,通过热压工艺来整体成型。结果表明:固化度为45.59%的Z-pin在热压过程中与蒙皮面板发生了交联-共固化反应,夹层结构的整体性得到显著提高;半固态Z-pin对K-Cor夹层结构压缩性能增强作用明显,高于其对拉伸性能的增强效果,这主要归因于高强度Rohacell-51WF泡沫芯材在压缩过程中起到支撑作用,可缓解Z-pin承载的部分应力;在拉伸或剪切过程中,主要承载对象为Z-pin,易折断之处位于Z-pin嵌入泡沫后折弯处的节点,受应力集中和表面缺陷等影响较大;当Z-pin植入角为45°、植入矩阵密度为[5 mm×5 mm]时,K-Cor夹层的剪切强度和模量增强效果最佳,较空白泡沫夹层分别提高约2.56倍和1.97倍;在平拉测试过程中,当Z-pin植入角为70°时,该夹层的平拉强度和模量为1.65 MPa和56.19 MPa,较植入角为60°和45°时试样的增强效果明显,这主要由于大的植入角有利于泡沫夹层在高载荷拉伸过程中保持稳定,分解了Z向轴向分力,促使Z-pin抗破坏能力增强。该泡沫夹层结构具有易于一体化热压共固化成型、可设计性强等优点,广泛适用于航天器羽翼和导弹外壳。Due to its excellent toughness and the cross-linking reaction for co-curing,partially-cured Z-pins currently are used as“Z”-directional reinforcing bat to strengthen foam-matrix sandwich structures.Through heat curing of the integrally-forming process to achieve a lightweight and high-strength foam sandwich structure which is widely used in spacecraft and missile shells to increase local bearing capacity and resistance to high-altitude electromagnetic radiation.The research of this paper was to explore a new-type K-Cor foam sandwich structure,as well as to study its strengthening mechanism of the as-received Z-pin within different curing degrees.The as-received K-Cor structures were fabricated by inserting Z-pin into Rohacell-51WF foam,using NHZP-1 and 5429/HT7 bismaleimides as pultrusion resin and pre-impregnated medium respectively.The experimental results show that Z-pin with a 45.59%curing degree had a cross-linking and co-curing reaction with skin panel during hot pressing,and the integrity of the foam sandwich structure was significantly improved.The results from shear tests indicate that as the Z-pin implantation angle at 45°and the implantation density as[5mm×5mm](abbreviated as 45°[5mm×5mm]),the shear strength and modulus of the K-Cor structures are 1.02 and 2.06 times higher than that of the blank foam.Great improvements on compression performance than tensile,this is mainly due to itself high strength of Rohacell-51WF foam core carrying some stress instead of Z-pin payload during the compression process.During the horizontal tensile test,as Z-pin implant angle at 70°,its tensile strength and modulus of K-Cor structure are 1.65 and 56.19 MPa,much higher than those at 60°and 45°,which is mainly attributed to the larger value of implantation angle to reduce the axial force along“Z”direction and increase the resistance to Z-pin failure during high load tensile processes.Overall,the lightweight and high-strength K-Cor foam sandwich structure is easily integrated with thermoforming and co-curi

关 键 词：半固态Z-pin K-Cor泡沫夹层 拉挤工艺 力学性能 

分 类 号：TB332[一般工业技术—材料科学与工程]