预浸料的铺放适宜性评价(一)——粘性篇

在自动铺带成型过程中,粘性和铺覆性是用于描述预浸料是否适合铺贴的两个重要因素,将粘性和铺覆性分别独立地研究能更好地理解预浸料的铺放适宜性。本文主要是针对预浸料的粘性进行探索,论述了预浸料粘性的物理意义,总结了当前国内外预浸料粘性的测量及表征方法,提出了以"平均剥离力"定量表征预浸料的粘性,并在自主搭建的试验平台上,研究了自动铺带成型过程中的主要工艺参数(取出时间、铺放压力、铺放速率、热风温度等)对预浸料粘性的影响。实验结果表明,在一定范围内,预浸料的粘性随取出时间先增大后减小,而随铺放压力的增加、铺放速率的减小、热风温度的升高而增大,为自动铺带工艺参数的控制提供了参考。     

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℃.     

预浸料的铺放适宜性评价(二)——铺覆性篇

在自动铺带成型过程中,粘性和铺覆性是用于描述预浸料是否适合铺贴的两个重要因素,将粘性和铺覆性分别独立地研究能更好地理解预浸料的铺放适宜性。本文主要针对预浸料的铺覆性进行了探索,论述了铺覆性的含义并总结了现有的预浸料铺覆性的定量表征方法,提出了以"最大弯曲力"定量表征预浸料的铺覆性,并通过三点弯曲试验研究了预浸料的粘弹性特征及自动铺带成型过程中的主要工艺参数(铺放速率、湿度、热风温度、老化时间等)对预浸料铺覆性的影响。实验结果表明,预浸料的铺覆性会随热风温度和湿度的升高而提高,随着老化时间和铺放速率的增加而减小。最后总结了铺覆性实验的工程意义,为自动铺带工艺参数的控制提供了参考。     

多因素作用下自动铺丝预浸料黏性变化规律

自动铺丝工艺是一种先进复合材料低成本、自动化成型制造工艺,其通常应用于制造飞机机身、S型进气道等大曲率复合材料构件。铺丝过程中,预浸料丝束黏性对铺丝产品最终质量有较大影响。一方面,丝束黏性不能过低,以保证预浸料之间顺利贴合。另一方面,丝束黏性也不能过高,以便于铺层失败时进行修改。目前,预浸料黏性评价方法以90°剥离试验与180°剥离试验为主,其主要针对自动铺带工艺中较宽的预浸带。前期初步试验表明,采用单丝束剥离试验法检测自动铺丝工艺中预浸料黏性时,数据会产生较大波动,无法满足相关检测要求。有鉴于此,本文首先建立自动铺丝预浸料黏性的检测准则,提出采用两丝束180°剥离试验检测预浸料黏性,然后基于该准则研究铺放压力、铺放速度、铺放温度、老化时间影响下丝束黏性的变化规律。     

关于若干工艺参数对铺带质量影响的研究

为分析自动铺带成型过程中铺放压力、铺放温度及铺放速度各工艺参数对铺放质量的影响,进而预测铺带过程中预浸带的形变,对带变形和带间隙进行微调控制以保证产品质量,本文在南航自行研制的自动铺带机上进行了一系列实验,并以预浸带黏性流动公式分析探讨了各因素的影响。研究结果表明,随着铺放温度的升高、铺放压力的增加和铺放速度的减小,预浸带变形量增加,带间隙减小,符合以预浸带黏性流动公式为基础的理论分析。     

值得关注的预浸料市场

预浸料是用控制量的树脂(热固性或热塑性)浸渍纤维或织物后形成的中间材料。浸渍技术有溶剂浸渍、热熔体浸渍、粉末浸渍等。预浸料可以"B阶"状态或部分固化后储存。预浸带或预浸布用于手糊、自动铺带、自动铺纤或某些缠绕成型工艺中。单向预浸带(所有纤维平行)是最常见的预浸料形式,它们提供单向增强。机织布及其他平面织物预浸料提供二维增强,它们一般成卷销售。还有用纤维预成型体和编织物制成的预浸料,它们提供三维增强。     

碳纤维复合材料厚壁管的成型工艺

本发明提供一种以碳纤维预浸料制作厚壁管的成型工艺,属于复合材料的成型工艺领域。本发明采用碳纤维预浸料进行剪裁、铺叠、卷管、缠带和固化,制成碳纤维复合材料厚壁管。本发明提供的成型工艺,使管件铺层设计不受限制,纤维在不同方向上的分布量可以精确控制,纤维角度可以设计。制备过程中不造成环境污染,成型后无需后期加工处理。制备的厚壁管质量轻、孔隙率低、纤维体积分数高、承载能力强。本工艺方法使用T700级碳纤维环氧型预浸料生产内经37 mm49 mm1 200 mm     

连续纤维增强聚苯硫醚预浸料自动铺丝工艺与热塑性复合材料性能研究

针对连续纤维增强的聚苯硫醚(PPS)预浸料的结晶行为、基本工艺性能等进行了测试和研究,并系统开展了基于该预浸料的自动铺丝工艺研究。文章总结了不同工艺条件对材料的结晶的影响和控制方法。通过考察不同自动铺丝参数对铺放质量的影响,建立了可靠的工艺方法。并开展了双曲率结构典型制件的铺放实验,指出了自动铺丝技术的关键技术和发展方向。     

不同双马树脂制备预浸料对复合材料单向板力学性能的影响

采用热熔预浸技术,对TR525型树脂和改性BMI型树脂制备了两种规格的东丽T700预浸料,测试了预浸料的物理性能,并且用DSC法测出了两种树脂的固化曲线,确定了树脂的固化制度。对东丽T700/TR525型预浸料和东丽T700/改性BMI型预浸料分别制备了复合材料单向板,对单向板力学性能进行了测试。结果表明,东丽T700/改性BMI型复合材料单向板0°拉伸强度、90°拉伸强度和层间剪切强度比东丽T700/TR525型复合材料单向板分别高出15.00%、87.39%和27.72%,达到了2391.22MPa、24.38MPa和84.86MPa。     

3234树脂预浸工艺研究

阐述了三辊逆向转移成膜法温度、时间等工艺参数与3234/803PV预浸料贮存期及工艺性能的关系。实验结果表明,适宜的成膜温度为65～75℃,相应的粘度为38～17Pa.s,3234树脂的流变特性和较宽的温度范围适应该成膜法,进而符合制备预浸料的要求。     

HDPE基芳纶增强复合带的制备

阐述了在不同的工艺条件下高密度聚乙烯(HDPE)基芳纶增强复合带的制备,并对制备的纤维复合带进行了力学性能测试。结果表明,运用韦伯(Weibull)统计方法研究不同工艺条件下制备的芳纶复合带的统计应力和形状参数是合适的;当处理温度为260℃,砝码压力为16.3 MPa,走丝速度为6 mm/s时,制备的复合带性能最佳。     

Properties of orthotropic glass–polypropylene composites manufactured by weaving of prepregtapes and other routes

Abstract

This paper reports a study of the melt impregnation and weaving of glass–polypropylene prepreg tapes into sheet for use as a precursor for pressed thermoplastic composite products and a comparison of the properties attainable with those achievable by other comparable routes. Melt impregnation has been used successfully to manufacture well impregnated tapes, with and without internal coupling agent. It appears that weaving could be an economically viable process for converting unidirectional tape into a conformable, press formable prepreg. The properties of glass–polypropylene laminates manufactured by pressing the tape woven product were compared with those of other glass–polypropylene composites, including crossply laminate made from Plytron and samples prepared by film stacking. Quasi-static mechanical properties were found to be comparable with those of Plytron and superior to those of the other materials. In the coupled samples, coupling was somewhat less effective than in Plytron. The impact behaviour of the pressed, tape woven products was impressive and superior to any of the other materials tested.     

连续玻纤增强聚丙烯预浸带熔融浸渍过程纤维断裂研究

为提高连续玻纤增强聚丙烯预浸带（PP/GF）性能,采用熔融浸渍法制备连续玻璃纤维增强聚丙烯预浸带,研究了PP熔体浸渍连续GF束过程。基于Weibull分布函数建立了纤维断裂数学模型,预测预浸带生产过程中纤维断裂率并描述实验结果。结果表明,模型与实验数据吻合较好,能够为工业化生产提供指导;纤维束在浸渍模具中受到树脂熔体的作用,及纤维与设备之间的摩擦是影响纤维断裂的主要因素,适当提高浸渍模具温度,降低纤维束牵引速度,增大浸渍模具间隙能有效降低纤维断裂率,提高工艺稳定性。     

Thermoforming of advanced thermoplastic composites. I: Single curvature parts

Thermoforming has been studied for a single curvature part made from various advanced thermoplastic matrix composite prepregs. For parts with acceptable shape conformity, preheating of the composite laminates to a processing temperature of 350 to 400°C is necessary prior to forming with molds maintained at 200°C. However, only PEEK/carbon fiber prepreg tapes yielded parts with acceptable microstructural integrity and a matrix crystallinity level of about 30 percent. Amorphous matrix based PXM 8505/T500 fabric prepregs also result in lamination and void free parts, but fiber matrix distribution in this case was rather poor. Parts thermoformed from other prepreg laminates contained voids and/or were delaminated, thereby indicating the need for higher mold temperature and forming pressure than that afforded by the present study, in which a standard lab-scale thermoforming machine was used.     

碳纤维（T700）/聚三唑树脂预浸带的储存性能表征与质量控制

利用红外光谱、液相色谱等分析技术研究了T700碳纤维/聚三唑树脂预浸带在不同储存时间与条件下物理化学特性的变化规律。研究表明,聚三唑树脂预浸带应在冷藏或冷冻环境下储存,以延长预浸带的使用期,满足大型构件制备要求。     

窄带预浸料制备工艺研究

简要介绍了8～34mm的窄带预浸料的制造工艺,并着重就影响窄带预浸料质量的几个主要参数,例如胶液温度,纤维运行速度,纤维张力进行了研究,并讨论了不同牌号、不同批次窄带预浸料的工艺稳定性。     

Quasi‐static and dynamic experiment investigations on the crashworthiness response of composite tubes

Crashworthiness performance of carbon and glass composite tubes have been comprehensive investigated under quasi‐static and dynamic axial crush testing. In this study, collapse modes and specific energy absorption (SEA) of different ply orientation of carbon fabric composites and unidirectional glass tubes were analyzed. For the weaker tensile strength and bending strength of glass composites, crack propagated approximately perpendicular to the fiber direction when the ply angle was small. Large amount of fibers breakage made the specific energy absorption over 80 kJ/kg under dynamic load. Thickness effect had inverse influence on SEA under different impact rate. The specific energy absorption declined as tube thickness increased under dynamic crush tests, however, increased under quasi‐static tests. Hybridization of glass/carbon tubes and carbon/carbon composites were analyzed by increased the axial fiber content. It was found that hybridization tubes of G803/3234 fabric and G827/3234 axial tapes with higher G827/3234 content present excellent energy‐absorption capability under dynamic and quasi‐static tests for all specimens tested. POLYM. COMPOS., 34:1099–1109, 2013. © 2013 Society of Plastics Engineers     

Mechanical Properties of Tape-Cast Alumina-Glass Dental Composites

Alumina-glass dental composites were prepared by tape casting and sintering at 1120°C, followed by glass infiltration at 1100°C. Flexural strength and fracture toughness of the composites were investigated in terms of the influence of tape constituents, namely, alumina powder, binder, and plasticizer, on the mechanical properties. Both strength and toughness increased with increasing alumina fraction in tapes and decreased with increasing binder content in binder/plasticizer mixtures. These observations were consistent with the influence of the constituents on mean alumina particle distance in tapes, suggesting that the high strength of glass-infiltrated alumina composites is related to toughening by crack bowing. The strength and fracture toughness of the tape-cast composites, optimized for forming dental crowns, were 508 MPa and 3.1 MPa·m^1/2, respectively, obtained from biaxial tests. Shrinkage of the composites decreased with increasing thermocompression pressure, applied to the tapes prior to sintering, and heating rate to the sintering temperature.