连续毡对风电叶片界面性能的影响分析

依据风电叶片主梁界面形成过程,采用真空辅助树脂灌注工艺制备层合板,选用层合板T剥离测试方法测试复合材料的界面性能。根据T剥离测试方法得到:真空辅助树脂灌注成型技术中,脱模布形成的界面上铺放连续毡,能够提高复合材料界面结合性能。最后,通过试样失效模式及显微结构分析得到与T剥离测试结果一致的结论,为连续毡在复合材料界面应用提供了参考。     

泡沫夹层结构VARI工艺中树脂流动行为的研究

采用可视化实验方法研究了泡沫夹层结构真空辅助成型工艺(VARI)中树脂的流动行为.结果表明,导流介质的存在可以明显提高树脂的流动速率;剥离布可使得复合材料泡沫样板表面光滑平整,并可明显提高充模速率,减少充模时间;增加浇注口数目可明显缩短充模时间,并可获得浸渍均匀、沟槽全满的样板.采用真空点源布局B时的树脂流动速率大于真...     

导流介质对VARTM复合材料纤维分布及空隙率的影响

研究了导流介质尺寸对真空辅助树脂传递模塑(VARTM)工艺中树脂流动行为的影响,以及对复合材料制品中纤维分布和空隙率的影响。结果表明,随着导流介质尺寸的增加,树脂在增强体中的流动速度加快,并呈现指数加速趋势;制品中纤维体积含量呈现先减少后增大的趋势,并且以导流介质边界为纤维体积含量高低的分界线;复合材料制品的空隙率范围在3.86%~19.92%,空隙率呈现先增大后减小再加速增大的趋势。     

玻纤编织布复合材料VARI工艺中树脂流动行为研究

采用可视化实验方法研究了玻纤编织布铺层真空辅助成型工艺中树脂的流动行为。结果表明,导流介质可提高树脂流动速率、缩短充模时间;边缘点浇注、树脂沿导流介质径向流动时流动前锋为抛物线且易产生白斑,树脂沿导流介质纬向浇注时流动前锋呈直线且不易产生白斑;中心点浇注只能缩短树脂沿导流介质径向流动的充模时间,整体充模时间并未得到改善;玻纤编织布为2层、4层、6层、8层时树脂流动速率相差无几。     

VARI成型厚度稳定与抽真空时间的研究

采用无接触式电涡流位移传感系统,对复合材料真空辅助成型过程中的厚度变化进行了实时监测。研究了在其他条件相同情况下,树脂粘度、充模距离、铺层厚度、铺覆导流网等对厚度稳定需要的最短抽真空时间的影响。结果表明,树脂注满并关闭树脂管以后,持续抽真空可有效提高真空辅助工艺成型纤维体积含量,且有利于减小沿树脂流动方向的厚度梯度;树脂粘度对厚度稳定所需要的最短抽真空时间影响最为明显,粘度越高需抽真空时间越长,充模距离、铺层厚度以及导流网对需要最短的抽真空时间影响相对较小。     

碳纤维增强环氧树脂复合材料的液体成型及其性能研究

本文研究了不同温度下RIM145树脂的粘度和适用期,分析了不同温度下RIM145树脂和碳纤维单丝之间的浸润性;并以碳纤维单向布为增强材料,采用真空辅助灌注成型工艺制备了碳纤维增强环氧树脂(CF/EP)复合材料,研究了复合材料的力学性能,对层间剪切试样剖断面形貌进行了SEM分析,并研究了使用VAP单向透气膜辅助真空灌注成型工艺对CF/EP复合材料厚制件灌注质量的影响。研究结果表明,RIM145树脂基体在50~70℃粘度低、适用期长且树脂与碳纤维单丝之间的浸润性良好,适用于CF/EP复合材料的真空辅助灌注成型工艺;灌注的CF/EP具有良好的力学性能,树脂和纤维具有中等粘结强度界面,采用VAP单向透气膜辅助真空辅助灌注成型工艺可降低CF/EP复合材料的孔隙率。     

先进树脂基复合材料RTM成型工艺研究及应用进展

复合材料的成型工艺是改进并提升先进树脂基复合材料性能的关键,而树脂传递模塑(RTM)成型工艺是一种环保高效、成本低、高精度的闭模成型工艺。概述并分析了传统RTM成型工艺过程及优缺点,并对高压树脂传递模塑成型(HPRTM)、轻质树脂传递模塑成型(LRTM)、真空辅助树脂灌注工艺(VARTM)、西门(Seeman)树脂浸渍技术(SCRIM P)等RTM衍生成型工艺的研究进展与应用进行了介绍分析。     

真空辅助树脂灌注工艺的创新性改进

真空辅助树脂灌注工艺是一种新型的复合材料低成本,高性能成型技术。由于其低成本、制品性能好、环境友好等独特的优势,真空辅助树脂灌注工艺已成功用于舰船、军事设施、国防工程、航空和风电等民用工业领域。但是这种工艺也有很多不可控制的因素,仍有许多需改进的地方。本文从树脂计量混合技术及制品表面质量控制等方面讨论了当今真空辅助树脂灌注工艺的一些创新性的改进。     

VARI液体成型复合材料机盖的数值模拟及工艺验证

针对复合材料机盖结构件进行了真空灌注(VARI)成型模拟,研究了不同注胶方案对注射时间的影响,以及导流网铺放和流道设计对树脂流动前锋和注胶过程的影响,优选出合理的注胶方式、导流网布局和流道设计,并进行工艺试验验证。结果表明,仿真模拟的树脂流动前锋与实际树脂的流动前锋趋势一致,而且均能将制件灌注完全,经检测满足成型制品性能要求,验证了工艺设计的合理性和模拟分析的有效性。     

真空辅助树脂灌注配套基体树脂的制备及性能

针对真空辅助成型技术(VARI)对基体树脂的特殊要求,结合航空材料对性能的高要求,研制了BA9912中温固化环氧树脂体系。采用VARI工艺制备了G0827/BA9912复合材料,测试了BA9912树脂浇注料及其复合材料的力学性能和耐热性能,并与国内外同类树脂进行了适当的比较分析。分析测试结果表明,BA9912树脂具有良好的力学性能、耐热性能和工艺性能,能够满足VARI成型工艺要求,适合在航空航天领域中应用。     

SCRIMP成型工艺研究

本研究建立了流动可视化试验装置,通过分析不同渗透介质型SCRIMP模塑条件和充模时间的试验结果,对渗透介质、剥离层、中空螺线管等因素对充模的影响进行了定性评价;将研究结果应用于1:1墙板的产品试制,总结了存在的问题和改进提高方法;建议在即定假设的前提下,利用2D CV/FEM模型预测大型制品的SCRIMP充模是下一步的研究方向.     

The Use of Peel Ply as a Method to Create Reproduceable But Contaminated Surfaces for Structural Adhesive Bonding of Carbon Fiber Reinforced Plastics

In the fabrication of fiber-reinforced plastics materials peel plies are commonly used as an additional layer on top of the laminates to sponge up the surplus resin and to create an activated surface for adhesive bonding or coating by peel ply removal. In theory, the peel ply removal results in a new and uncontaminated fracture surface that is activated by polymer chain scission. The peel ply method is often presented as being a good surface treatment for structural bonding.

In this study carbon fiber-reinforced plastics (Hexcel® 8552/ IM7) were produced by the use of five different peel plies and a release foil made of polytetrafluorethylene (PTFE). The peel plies themselves and the surfaces on the CFRP created by peeling were examined by scanning electron microscopy (SEM), x-ray photo electron spectroscopy (XPS), energy-dispersive x-ray spectroscopy (EDX), infrared (IR) spectroscopy, atomic force microscopy (AFM), and contact angle measurements to characterize the surfaces produced. Furthermore, the bond strength of lap shear and floating roller peel samples was determined with and without additional plasma treatment. For bonding, a room temperature-curing two-component-epoxy adhesive (Hysol® 9395) was used to prove the applicability of different peel plies for structural adhesive bonding under repair conditions.     

The peel ply surface treatment for adhesive bonding of composites: A review

This paper reviews existing literature related to the peel ply surface treatment of composite materials. A peel ply fabric is used as a removable layer in a composite lay-up and ripped off to modify the surface for adhesive bonding. A peel ply can affect the elemental composition of a surface and it is possible to distinguish between either a polyester or a polyamide peel ply treatment for a specific composite system and application. However, consistent and generalised relationships between the compositional modification or the surface energy and adhesive or resin adherence to treated surfaces are not probable. A compositional analysis and surface energy measurements are affected by the fractured matrix, peel ply fibre cavities and revealed reinforcements. Only a few recent studies have presented results for the regions of the matrix fracture and fibre cavities separately. Resin-impregnated peel plies, namely tear plies, offer additional tailorability for composite surface treatments, but related research is scarce.     

真空辅助成型技术及其配套基体树脂研究进展

综述了国内外关于真空辅助成型技术(VARI)及其配套基体树脂的研究和应用状况,介绍了VARI成型技术的主要原理、工艺流程及其对基体树脂的基本要求,并对国内外在VARI成型技术和配套基体树脂领域中的进展进行了适当的比较和分析。     

VARI工艺在建筑物加固修复上的应用

本文叙述了VAR I工艺特点及其用于建筑物加固修复的重要性、优越性和应用前景。自制了一套简易实验装置,归纳并阐述了建筑物加固修复用VAR I技术的主要内容。针对国内的情况,提出了该领域亟待开展的研究工作。     

Mode I fracturing properties of epoxy bonding paste

The wedge-splitting method by Tschegg was applied for the investigation of mode I fracture behavior of epoxy-based adhesives. Specific fracture energy and notch tensile strength of “traditional” thickened laminating resin were measured between −40 and +45 °C and compared to those of four new trial compounds. The adhesives in bulk were investigated as well as the interfaces between these adhesives and glass fiber-reinforced plastic. The wedge-splitting method has turned out suitable for epoxy resin. The quality of thickened laminating resin was not reached by the new trial compounds. Adherend pre-treatment with laminating resin and peel ply improved interfacial properties.     

复合材料增强纤维渗透率测量及VARI成型工艺仿真计算研究

针对纤维增强树脂基复合材料真空辅助成型( VARI)工艺仿真计算,根据Darcy定律推导出了增强纤维渗透率的常用计算公式,并根据该公式完成了渗透率值的测量,在此基础上,针对某复杂结构模型的VARI工艺分别完成了仿真计算和验证试验,最后对计算结果与验证试验结果进行了比较,结果表明二者基本吻合,验证了工艺仿真计算的有效性.     

真空辅助树脂注射成型(VARI)研究进展

复合材料低成本制造工艺中,VARI是一种很重要的成型技术,本文对VARI的优点、难点、专用树脂体系、成型方法、树脂分配系统、树脂流动模拟及其国内外应用进行了综述.研究表明,VARI作为一种复合材料的低成本成型技术,已得到广泛应用,尤其是大尺寸、大厚度制件的制造.发展VARI工艺对于降低复合材料的制造成本、扩大复合材料的应用范围有很大作用.由于VARI常用于大尺寸结构件的制造,树脂充模过程的精确模拟对制品质量至关重要,目前国内对此研究仍停留在初级阶段,该方面研究需要引起重视.     

Effects of the addition of a cover mold on resin flow and the quality of the finished product in vacuum‐assisted resin transfer molding

For vacuum‐assisted resin transfer molding (VARTM), we propose adding a cover mold, inserted between the distribution medium and the peel ply, to achieve a higher fiber volume fraction in the final product. As the conventional VARTM process does not use a cover mold, improved processes using different rigid covers were explored. A three‐dimensional digital image correlation system was developed to monitor the thickness evolution of the vacuum package during the infusion stage. This system was validated as a full‐field displacement test. The results demonstrate that there are three advantages to using a cover mold. First, in the filling stage, a rigid cover mold can prevent shrinkage of the part at the resin flow front, and even cause slight expansion of the unsaturated part. This improves the resin flow and shortens the time required for complete infusion. Second, a cover mold can limit the amount of excess resin needed to infuse the saturated part. Third, in the postfilling stage, the cover mold can be used to accelerate extrusion of the excess resin in the package. The overall effect is to increase the fiber volume fraction in the final product. POLYM. COMPOS., 37:1435–1442, 2016. © 2014 Society of Plastics Engineers