自动铺放过程双马树脂预浸料温度与黏度

通过对自动铺放成型工艺的分析,探索了自动铺带成型过程中预浸料温度对复合材料黏性的影响规律。对影响预浸料温度的热风温度和铺放速度两个因素进行了研究,从理论上建立了热风加热温度和铺放速度与预浸料温度之间的关系,提出了控制预浸料温度的具体实施方案,指导自动铺带成型过程。根据双马树脂预浸料黏度和温度曲线,分别在不同的热风温度和铺放速度条件下进行实验,得到在热风温度为90℃、铺放速度为10~20m/min时,预浸料黏度满足铺覆性要求,验证了预浸料热风温度和铺放速度对复合材料制品质量的影响,为自动铺带工艺提供参考。     

零吸胶炭纤维增强高温固化环氧复合材料预浸料研制

针对大尺寸、大厚度复合材料构件对“零吸胶”预浸料的需求,对低树脂含量炭纤维增强高温固化环氧复合材料预浸料进行了研制,并对预浸料的外观和物理性能、复合材料基本力学性能及成型工艺性能进行了研究.通过对预浸料制造工艺参数的优化,研制出了低树脂含量炭纤维增强高温固化环氧复合材料预浸料,其外观和物理性能满足要求;采用低树脂含量预...     

YPH-23环氧树脂/预浸料的等温固化动力学研究

针对预浸料碳纤维树脂基复合材料成型的特点,采用差示扫描量热法(DSC)研究了碳纤维/YPH-23环氧树脂预浸料的DSC曲线,并与纯树脂的DSC曲线进行对比分析。研究结果表明:预浸料的DSC曲线与纯树脂存在差异;预浸料在130~160℃范围内的固化反应符合自催化固化反应模型,固化反应活化能为45.560kJ/mol;预浸料的动力学研究结果更能反映实际复合材料制造成型过程中的特征,可为实际复合材料的成型工艺优化提供参考。     

石墨烯改性碳纤维树脂基复合材料的制备和性能评价EI北大核心CSCD

以石墨烯预浸料作为功能层,铺贴在碳纤维预成型体表面,通过热压罐共固化成型的方法,制备石墨烯改性碳纤维树脂基复合材料。利用超声扫描、金相电镜、四探针、矢量网络分析仪和万能材料试验机等测试手段研究石墨烯预浸料对复合材料内部质量、电磁屏蔽性能和力学性能的影响。实验结果表明:石墨烯预浸料的加入,并不会影响到复合材料的内部质量,并且石墨烯功能层和碳纤维结构层之间具有良好的界面相容性。在此基础上,石墨烯预浸料作为功能层,利用其优异的导电性能,可以使得复合材料的电磁屏蔽性能显著提高。当加入G105/3234石墨烯预浸料时,复合材料的电磁屏蔽效能由27.7 dB提高到64.7 dB。与此同时,改性后的碳纤维树脂基复合材料仍然可以保持良好的力学性能。     

干纤维自动铺放-液体成型技术进展研究

相较于传统预浸料预制体需要热压罐固化，干纤维自动铺放结合液体成型技术可以实现非热压罐制造复合材料，从而降低制造成本、缩短制造周期。本研究针对干纤维自动铺放-液体成型技术，从干纤维铺放材料、干纤维自动铺放设备以及干纤维自动铺放工艺技术进展三个方面进行概述，并对其未来在船舶领域的应用进行展望。     

先进树脂基复合材料制造技术进展

国内先进树脂基复合材料制造技术经过30多年的发展,已初步形成以热熔预浸料制造、热压罐和树脂传递模塑(RTM)成型技术为代表的先进树脂基复合材料制造技术体系,所制备的先进树脂基复合材料已在航空领域得到大量应用.本文中主要介绍国内先进树脂基复合材料热压罐成型技术、RTM成型技术和自动铺放技术的最新进展以及先进树脂基复合材料制造过程模拟与优化技术,讨论了国内先进树脂基复合材料制造技术的主要发展方向.     

先进树脂基复合材料制造技术进展

国内先进树脂基复合材料制造技术经过30多年的发展, 已初步形成以热熔预浸料制造、 热压罐和树脂传递模塑(RTM)成型技术为代表的先进树脂基复合材料制造技术体系, 所制备的先进树脂基复合材料已在航空领域得到大量应用。本文中主要介绍国内先进树脂基复合材料热压罐成型技术、 RTM成型技术和自动铺放技术的最新进展以及先进树脂基复合材料制造过程模拟与优化技术, 讨论了国内先进树脂基复合材料制造技术的主要发展方向。     

热塑性复合材料自动纤维铺放装备技术

基于热塑性复合材料(TPC)自动纤维铺放(AFP)原位固结技术,开展热塑性复合材料AFP装备技术研究,分析AFP平台的功能需求,提出平台总体规划方案,设计开发热塑性复合材料自动铺丝头,并提出预浸纱张力控制方案、精确送纱及温度闭环控制方案。在此基础上,设计AFP系统可行性验证实验,证明方案的可行性和平台的实用价值。结果表明:本实验平台针对热塑性复合材料铺放特点,优化张力与铺放速度匹配,实现预浸纱动态恒张力铺放,确保成型构件质量;实验平台调控铺放速度与送纱协调,实现精确定位,保障成型构件尺寸;建立了铺放速度与加热功率、热流分布关系,实现高精度温度场分布控制。虽AFP成型构件的力学性能比热模压成型构件的力学性能低约20%,但为热塑性复合材料AFP装备技术的广泛应用奠定了基础。     

取向碳纳米管膜/氰基树脂复合材料的制备与性能强化机制

以浮动催化化学气相沉积法(FCCVD)碳纳米管(CNT)膜为原料,通过氰基树脂溶液浸渍法制备CNT预浸膜,然后采用热辅助牵伸和热压固化的方法制备高取向CNT膜复合材料。详细分析了热处理的温度和树脂溶液浓度对CNT预浸膜拉伸性能的影响,从而得到合适的热辅助牵伸工艺,并考察固化工艺对复合材料性能的影响。在此基础上,从浸润特性、CNT取向程度和层间剪切性能方面揭示CNT膜复合材料力学性能的强化机制。结果表明与传统CNT膜牵伸工艺相比,CNT预浸膜热牵伸工艺更有利于制备高取向CNT膜复合材料。热牵伸的温度和树脂溶液的浓度是制备高取向、低孔隙CNT预浸膜的关键因素。通过固化工艺的改变可有效调控氰基树脂的反应程度碳纳米管薄膜/氰基树脂复合材料的拉伸性能。经高温后固化处理后,CNT膜/氰基树脂复合材料的拉伸强度和模量分别高达2 748 MPa和302GPa。优异的树脂浸润特性、层间剪切强度以及高的CNT取向度使CNT膜复合材料中CNT更有利于协同承载,从而提高其力学性能。     

热压罐工艺树脂压力测试系统适用性实验研究

采用玻璃纤维织物/环氧树脂E51预浸料研究热压罐工艺树脂压力在线测试系统适用性,分析了树脂黏度对测试系统动态反应特性的影响,进而测试了热压罐工艺零吸胶条件下等厚、非等厚及L形预浸料铺层内部的树脂压力,并与理论模型计算树脂压力对比,以分析测试系统的准确性。结果表明: 树脂黏度明显影响系统的动态反应特性,当树脂黏度低于25 Pa·s时树脂压力测试系统具有较高的动态反应特性,满足复合材料内部树脂压力测试需求; 对于所研究的各种形式的预浸料铺层,树脂压力测试值与理论值有很好的一致性,当热压罐压力达到0.5 MPa,相对误差约为2%,验证了系统的准确性。     

Resin Flow of an Advanced Grid-Stiffened Composite Structure in the Co-Curing Process

The soft-mold aided co-curing process which cures the skin part and ribs part simultaneously was introduced for reducing the cost of advanced grid-stiffened composite structure (AGS). The co-curing process for a typical AGS, preformed by the prepreg AS4/3501-6, was simulated by a finite element program incorporated with the user-subroutines ‘thermo-chemical’ module and the ‘chemical-flow’ module. The variations of temperature, cure degree, resin pressure and fiber volume fraction of the AGS were predicted. It shows that the uniform distributions of temperature, cure degree and viscosity in the AGS would be disturbed by the unique geometrical pattern of AGS. There is an alternation in distribution of resin pressure at the interface between ribs and skin, and the duration time of resin flow is sensitive to the thickness of the AGS. To obtain a desired AGS, the process parameters of the co-curing process should be determined by the geometry of an AGS and the kinds of resin.     

非热压罐工艺模具对复合材料加筋壁板固化变形影响的有限元分析

通过真空袋成型工艺,利用CYCOM 5320-1材料体系制备了碳纤维/树脂基复合材料T型加筋壁板,并应用激光跟踪仪测量了其固化变形量。针对考虑模具影响和不考虑模具影响两种情况,利用有限元方法模拟了该加筋壁板固化过程。结果表明：数值模拟固化变形趋势和实验结果趋势相同,在宽度方向上吻合较好。考虑模具因素比未考虑模具因素的模拟结果更接近真实变形值,这是由于复合材料在达到树脂凝胶点之前,模具受热挤压模腔,导致构件产生永久性变形造成的。     

Cure behaviour and void development within rapidly cured out-of-autoclave composites

This study investigates the effect of slow and fast heating rates (1.5 and 10 °C/min) on the formation of voids during the out-of-autoclave curing process of an aerospace composite (HexPly 8552). The cure cycles were interrupted at pre-defined stages for each heating rate enabling the in situ behaviour of the resin, void content and growth of voids to be studied. It was found that the morphology and content of voids remained unchanged up to the second heating stage of the cure cycle, regardless of heating rate. Thereafter, differences to minimum resin viscosity for the faster heating rate (5.2 Pa s compared to 32.5 Pa s) and a higher gelation temperature (177 °C compared to 160 °C) caused a slight increase to void growth for the rapid curing conditions. The causes of voids were the result of moisture volatiles contained within the prepreg, identified by mass spectrometry. Overall, the faster heating rate reduced the cure cycle time by 32% without any effect on the final degree of cross-linking (88.4%) or overall void content, which remained below 2%.     

Out-of-autoclave cure cycle study of a resin film infusion process using in situ process monitoring

Liquid resin infusion (LRI) of textile tailored reinforcements (TRs) is increasingly applied in new processing technologies for manufacturing carbon fibre composites. This work presents a cure cycle study of an out-of-autoclave toughened resin film infusion (RFI) process as part of the examination of an alternative manufacturing process for composites. To successfully produce laminates using resin film infusion in combination with a fast-curing process, the flow behaviour of the selected resin material under changed processing conditions was investigated. The effect of processing parameters, specifically heating rates and dwell times, on resin viscosity and laminate infiltration was evaluated through experimental work and supported by in situ process monitoring. A DC-resistance sensor system was applied to track the change in resin viscosity during cure. Results showed that cure cycles with a relatively short dwell time and higher heating rate compared to an autoclave cure led to enhanced flow properties of the toughened resin system. High quality laminates, comparable to autoclave panels, were manufactured with vacuum pressure only by modifying the original vacuum bagging arrangement.     

Low-energy electron beam cured tape placement for out-of-autoclave fabrication of advanced polymer composites

The autoclave curing process for advanced polymer composites is labor and capital intensive, with the curing cost increasing dramatically by the growth in part size. In order to develop an out-of-autoclave (OOA) fabrication process for advanced polymer composites, a new process integrating automated tape placement with low-energy electron beam radiation curing was explored, by which in situ layer-wise curing of advanced composites can be achieved with the tape placement process. The irradiation process was optimized to get a homogenous curing, by tuning the electron beam dose-depth distribution in the prepreg material. Besides, the curing characteristics of the prepreg material by the low-energy electron beam irradiation was investigated and effect of exposure dose and post curing on curing degree, glass transition temperature (Tg) and interlaminar shear strength (ILSS) were characterized experimentally.     

光纤微弯压力测试系统实时监测复合材料热压成型过程

利用自行研制的光纤微弯压力测试系统, 对树脂基复合材料热压成型过程进行实时监测。实验结果表明, 该系统除了能较好地反映垂直层板方向压力变化外, 还能提供加压过程树脂流动状态及层板密实达到稳态均匀时间的相关信息。这些结果对确定合理加压点及保压时间、优化工艺参数、控制复合材料成型构件质量具有十分重要的意义。      

A process model for the compaction and saturation of partially impregnated thermoset prepreg tapes

Automated manufacturing of composite materials is key to reducing cost and improving consistency in part quality. Modeling of manufacturing processes can identify influential material, geometric, and process variables, while providing a framework for their optimization and control. A process model has been formulated to describe the compaction and saturation of partially impregnated thermoset prepreg tapes during their placement, using a roller compaction and vacuum consolidation. The roles of various parameters that characterize the initial prepreg tape state and the final prepreg tape state are investigated. The model yields the degree of resin saturation in the tape with changes in its thickness after being compacted, due to an external pressure. The results estimate the degree of dry fiber region within the tape, which can provide vacuum pathways for air or volatile removal before consolidation and cure. The model can be adapted for different material constitutive relationships of tape compaction and saturation.     

碳纤维/环氧树脂预浸带铺放应力场及制品微观结构的模拟与实验

碳纤维/环氧树脂预浸带复合材料在铺放成型时,由于树脂基体与碳纤维之间的热膨胀系数存在差异以及成型时热-力参数作用下由于纤维的变形而导致纤维与基体接触处产生应力集中等原因,在制品材料中会产生热残余应力。针对碳纤维/环氧树脂预浸带复合材料的实际结构特点,利用ABAQUS有限元软件建立含有界面的碳纤维/环氧树脂预浸带复合材料的细观代表性体积单元(Representative volume element, RVE)有限元模型,采用实验研究和有限元仿真分析的方法,研究在温度-压力参数作用下预浸带铺放制品残余应力的分布规律及影响机理。首先,建立预浸带铺放时的温度和压力模型,研究不同温度和压力参数条件下碳纤维/环氧树脂预浸带铺放制品残余应力的分布情况。其次,采用耦合降温法模拟碳纤维/环氧树脂预浸带残余应力随纤维体积含量、铺放压力以及铺放温度的变化规律,并采用扫描电镜对不同工艺参数条件下预浸带铺放制品的微观结构进行分析。通过对模拟结果进行分析比较得到各因素对制品残余应力的基本影响规律;最后进行不同温度和压力等铺放参数对预浸带铺放成型时残余应力影响的实验测试研究。      

基于折射率变化的固化在线监测研究

先进复合材料的固化成型工艺十分复杂,目前在很大程度上仍依赖于经验工艺。为了实现复合材料固化工艺的透明化、科学化及智能化,提出了将光纤折射率传感器用于复合材料制造过程,研制了一种折射率光纤传感器,同时将光源、探测器、信号处理器等元器件集成化为一个便携式的光纤传感仪以利于生产现场使用。利用该传感器对常温固化树脂的固化过程进行了测量,将其与同等条件下迈克尔逊干涉仪对固化过程的监测结果进行了比较,二者具有良好的一致性。在实验室与生产现场两种条件下将光纤折射率传感器埋设于预浸料中对其固化工艺过程进行了监测。结果表明,该技术不仅可以用于新型树脂固化工艺制度的确定,也可用于复合材料固化工艺过程的在线监测。