国产MT700碳纤维复合材料螺栓连接强度实验研究

对国产MT700与进口T700S碳纤维复合材料单螺栓连接结构的静拉伸强度进行实验研究,分析了两种材料的载荷-位移曲线特征、连接强度特性及破坏形式。实验结果表明:国产MT700/603层合板连接部位的承载能力及结构稳定性均优于进口T700S/603层合板,M5及M6单螺栓连接破坏强度分别提高了12%和10%;另外,国产MT700/603层合板胶-螺混合连接有效提高了整体连接强度和安全设计裕度,胶层破坏后,M5与M6单螺栓胶-螺混合连接剩余强度系数分别达到65%和88%。     

T700／3234层合板力学性能的研究

研究了T700／3234层合板力学性能,T700／3234层合板铺层45°／-45°／0°／90°／0°／0°／90°／0°／-45°／45°.T700／3234中温固化环氧碳纤维单向预浸料适应于热压罐成型工艺方法.测试了23℃、60℃、80℃、100％下,T700／3234层合板拉伸性能、压缩性能、弯曲性能、层间剪切强度及层合板的拉伸剪切强度,得出不同温度下层合板各项力学性能的保持率,表明：T700／3234复合材料使用温度不大于80℃.     

RFI工艺成型碳NCF/环氧5228A复合材料研究

借助流变仪和差示扫描量热仪分析5228A环氧树脂膜的性能,以此为参考制定树脂膜渗透成型工艺(RFI)的固化制度;制备并测试增强材料为T700-12k碳纤维无屈曲织物(NCF)、铺层方式为[(0,90)/(±45)]s的层合板力学性能,其层间剪切强度比相应的无纬布层合板高25.3%;在层合板研究的基础上成功研制了规格为1000×200×37mm的帽形梁;利用超声波无损检测和金相显微检查等手段检测帽形梁的质量,检测结果显示,帽形梁材质致密、内部无明显缺陷,将应用于某型号卫星主承力结构。研究表明,5228A环氧树脂膜具有良好的工艺性,RFI工艺能够应用于复合材料复杂结构件的制造。     

薄型碳纤维织物预浸料及其复合材料研究

采用国产1k T300级薄型碳纤维织物和中温固化高性能树脂制备预浸料。测试了该预浸料及其复合材料性能,并与国产3k T300级碳纤维织物预浸料及其复合材料性能进行对比。研究结果表明:国产1k T300级薄型碳纤维织物的复合材料性能与国产3k T300级碳纤维织物的复合材料性能相当;该薄型碳纤维织物复合材料的树脂体系是改性增韧环氧树脂,韧性好,适用于轻质夹层结构复合材料,具有较高滚筒剥离强度;同时,该轻质复合材料耐热性好,玻璃化转变温度能达到200℃。     

国内外T700级碳纤维及其复合材料的性能

分别以国产T700S-12K碳纤维与东丽T700S-12K碳纤维为基体,在相同的制备条件下制得纤维复丝及其复合材料,对比研究了两种碳纤维的复丝强度和复合材料性能。结果表明:SYT49碳纤维复丝拉伸强度与模量达到同级别东丽T700级碳纤维;SYT49碳纤维板材拉伸、压缩、层剪和弯曲性能均要接近或优于东丽T700S-12K碳纤维复材,说明国产工业化生产碳纤维SYT49在一定程度上可以取代东丽同级别碳纤维。     

中小型无人机用国产碳纤维复合材料拉伸性能研究

研究测试了不同国产碳纤维预浸料的拉伸性能,包括T700中温固化0°/90°拉伸性能、T700高温固化0°/90°拉伸性能、T800高温固化0°/90°拉伸性能。0°拉伸强度最大达到2062Mpa(江苏恒神),拉伸模量最大139GPa, 90°拉伸强度最大51Mpa,拉伸模量9.15GPa, 0°压缩强度最大1171MPa,压缩模量130GPa, 90°压缩强度最大达到187MPa,而T700和T800高温固化国产碳纤维的性能更加优异,0°拉伸强度高了将近1500MPa,拉伸模量提高了将近100GPa左右。结果表明,目前国产T700中温固化碳纤维预浸料力学性能基本与进口材料相当,大于中小型无人机拉伸性能设计准则,能够满足中小型无人机的结构设计和生产。     

低成本中温固化湿法缠绕用树脂基体及其国产碳纤维复合材料

针对国产T700碳纤维、中温固化及湿法缠绕的特点,制备了一种适合国产T700碳纤维湿法缠绕用的低成本树脂基体,研究了树脂基体热性能、力学性能、使用期和成本,测试了该树脂基体与国产T700碳纤维制备的复合材料的力学性能。结果表明:该树脂体系耐热性良好且力学性能优异,适宜中温固化,粘度和使用期满足湿法缠绕工艺要求,成本降低超过65%;该树脂基体与国产T700碳纤维制备的复合材料力学性能优异,0°拉伸强度为1988.15 MPa,0°压缩强度为821.02 MPa,弯曲强度为1839.94 MPa,剪切强度为89.51 MPa。     

T700/LT-03A层合板在不同环境下的拉伸性能研究

在室温、低温和湿热三种环境下,对碳纤维层合板分别开展了静力和拉-拉疲劳试验。得到了T700/LT-03A层合板的拉伸性能和破坏机理。在抗拉强度和抗疲劳性能方面,室温环境优于其它两种环境。试验和模拟结果表明:T700/LT-03A层合板在三种环境下的应力结果较为接近;与室温环境下的结果相比,低温和湿热环境下层合板的应力分别减少了3.37%和4.3%,而湿热环境下层合板的应力增大了5.69%。环境对该层合板的疲劳性能影响较大。研究成果对碳纤维复合材料的工程应用提供一定的参考。     

薄层碳纤维织物预浸料的制备与性能

通过超声波扩展技术将T700-12K碳纤维扩展成20mm宽,然后利用全自动编织机编织成平纹布,最后采用后浸渍法中的胶膜法制备高性能YPH-69/T700和SZ-125/T700的织物预浸料。预浸料的单位面积纤维质量为(80±3)g/m~2,单层固化厚度为(0.080±0.015)mm。通过模压工艺制备层合板测试力学性能,结果表明:利用SZ-125树脂制备的层合板比用YPH-69树脂制备的层合板力学性能好,与树脂的性能密切相关。同时用abaqus软件建立有限元模型,研究在拉伸、压缩载荷下复合材料层合板的应力分布,模拟结果与实验过程中断裂位置相符。     

短纤维层间增强碳纤维复合材料层板的力学研究

以斜纹3k T300碳纤维布、环氧树脂和0.3~0.5 mm短切碳纤维为主要实验原料,使用短切纤维铺放装置将短切碳纤维定量铺放在碳纤维布表面,并铺层得到5块层间短切纤维增强的预制体,每块预制体含8层碳纤维布且每块预制体层间短切碳纤维铺放面密度分别为5,10,20,30,40 g/m2,并增设一块层数为8层、层间不含短切纤维增强的预制体作为对照组。采用真空辅助树脂灌注成型方式浸渍预制体后高温固化,得到层间含不同面密度短切纤维的碳纤维复合材料层合板,研究了不同面密度短切纤维含量对碳纤维复合材料层合板拉伸、弯曲以及层间剪切强度的影响。研究结果表明,当短切碳纤维铺放面密度为5 g/m2时,复合材料层板的拉伸、弯曲强度最好,在5~40 g/m2范围内,复合材料层板的层间剪切强度随短切碳纤维铺放面密度的增大而增大。     

Comparison of mechanical properties of epoxy composites reinforced with stitched glass and carbon fabrics: Characterization of mechanical anisotropy in composites and investigation on the interaction between fiber and epoxy matrix

The primary purpose of the study is to evaluate and compare the mechanical properties of epoxy‐based composites having different fiber reinforcements. Glass and carbon fiber composite laminates were manufactured by vacuum infusion of epoxy resin into two commonly used noncrimp stitched fabric (NCF) types: unidirectional and biaxial fabrics. The effects of geometric variables on composite structural integrity and strength were illustrated. Hence, tensile and three‐point bending flexural tests were conducted up to failure on specimens strengthened with different layouts of fibrous plies in NCF. In this article, an important practical problem in fibrous composites, interlaminar shear strength as measured in short beam shear test, is discussed. The fabric composites were tested in three directions: at 0°, 45°, and 90°. In addition to the extensive efforts in elucidating the variation in the mechanical properties of noncrimp glass and carbon fabric reinforced laminates, the work presented here focuses, also, on the type of interactions that are established between fiber and epoxy matrix. The experiments, in conjunction with scanning electron photomicrographs of fractured surfaces of composites, were interpreted in an attempt to explain the failure mechanisms in the composite laminates broken in tension. POLYM. COMPOS., 2008. © 2008 Society of Plastics Engineers     

Polyester composites reinforced with noncrimp stitched carbon fabrics: Mechanical characterization of composites and investigation on the interaction between polyester and carbon fiber

The primary purpose of the study is to investigate the anisotropic behavior of different noncrimp stitched fabric (NCF) reinforced polyester composites. Carbon fiber composite laminates were manufactured by vacuum infusion of polyester resin into two commonly used advanced noncrimp stitched carbon fabric types, unidirectional and biaxial carbon fabric. The effects of geometric variables on composite structural integrity and strength were illustrated. Hence, tensile and three‐point bending flexural tests were conducted up to failure on specimens strengthened with different layouts of fibrous plies in NCF. In this article an important practical problem in fibrous composites, interlaminar shear strength as measured in short beam shear tests, is discussed. The fabric composites were tested in three directions: at 0°, 45°, and 90°. Extensive photomicrographs of multilayered composites resulting from a variety of uniaxial loading conditions were presented. It was observed that broken fibers recede within the matrix in composites with weak interfacial bond. Another aim of the present work was to investigate the interaction between carbon fiber and polyester matrix. The experiments, in conjunction with scanning electron photomicrographs of fractured surfaces of composites, were interpreted in an attempt to explain the instability of polyester‐resin–carbon‐fiber interfaces. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 102: 4554–4564, 2006     

碳纤维表面性能对界面黏结强度的影响浅析

为了解碳纤维表面性能对纤维-树脂界面黏结强度的影响,使用扫描电镜、原子力显微镜与X射线光电子能谱仪(XPS),对国产T-300级碳纤维、台丽TC36S碳纤维、东丽T700S碳纤维的表面进行物理与化学表征,得出:国产碳纤维与TC36S碳纤维表面形貌相近,而T700S表面比较光滑;XPS定量分析技术表明3种碳纤维表面的活性差异较大,碳纤维与树脂的界面黏结强度随纤维粗糙度和表面活性官能团而变化。     

Structural degradation and mechanical fracture of hybrid fabric reinforced composites

This investigation involves the study of accelerated environmental aging in two polymer composite laminates reinforced by hybrid fabrics based on carbon, Kevlar and glass fibers. Composite laminate configurations are defined as a laminate reinforced with E‐glass fiber and Kevlar 49 fiber hybrid fabric (GK) and another laminate reinforced with E‐glass fiber and AS4 carbon fiber hybrid fabric (GC). Both laminates were impregnated with epoxy vinyl ester thermosetting resin (Derakane 470‐300) consisting of four layers. Morphological studies (photo‐oxidation process and structural degradation) of environmental aging were conducted, in addition to comparative studies of the mechanical properties and fracture characteristics under the action of uniaxial tensile and three‐point bending tests in specimens in the original and aged conditions. With respect to uniaxial tensile tests for both laminates, good mechanical performance and little final damage (small loss of properties) was caused by the aging effect. However, for the three‐point bending tests, for both laminates, the influence of aging was slightly higher for all parameters studied. The low structural deterioration in the laminates is attributed to the high performance with the heat of the matrix (Derakane 470‐300) and the characteristics of the hybrid fabric, exhibiting fiber/matrix interface quality. POLYM. ENG. SCI., 56:657–668, 2016. © 2016 Society of Plastics Engineers     

高强聚丙烯腈碳纤维复丝拉伸强度的测试

以东丽T700SC-12K碳纤维为样品,详细研究了碳纤维复丝拉伸测试过程中影响制样的因素,主要包括环境温度和湿度、胶液配比、浸胶时间、加强片以及样条和加强片固化温度。结果表明:随湿度增加,碳纤维拉伸强度下降;配置胶液时需选择合适的配比;浸胶时间长短对碳纤维拉伸强度影响不大;加强片厚度选择要适中;样条和加强片固化温度高会造成碳纤维拉伸性能的下降。     

碳纤维拉伸模量准确测试研究

分析了碳纤维拉伸模量测试中存在的问题,表明引伸计是准确测试碳纤维拉伸模量的必要设备。通过对T800-12K碳纤维拉伸模量测试结果的分析比较,认为应变范围的选择直接影响模量的计算结果,在应变范围为0.2%~0.7%时,可以获得具有与标称值很好一致性的结果。拉伸形变速率对模量测试结果具有一定影响,研究表明拉伸形变速率约0.1/min对于碳纤维拉伸模量测试较为合适。     

加捻对T800碳纤维拉伸性能的影响

要通过对日本东丽1700、T800碳纤维复丝拉伸性能的表征主要研究了加捻对,T800碳纤维拉伸性能的影响。研究结果表明：采用浸胶后加捻的方式有助于改善T800碳纤维的拉伸性能,合适的捻度可使其拉伸强度提高5％,断裂延伸率提高10％。并通过对rr800碳纤维干纱加捻的研究基本确定了T800碳纤维的临界捻度为15n／m。     

(±45°/90°/0°)_s准各向同性层合板的拉伸强度

根据经典层合板理论,层合板(±45°/90°/0°)s是准各向同性层合板,其拉伸刚度在板面内各个方向上都相同,而拉伸强度是随偏轴角θ改变而变化,即强度方面不具有各向同性的特点。本文首先研究(±45°/90°/0°)s这种准各向同性层合板拉伸强度在偏轴角θ从0°至45°之间的变化情况,然后通过分别改变单层板强度参数和弹性常数来研究该层合板的拉伸强度的变化情况,并分析其破坏形式。最后与NCF材料的试验结果进行了比较。