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碳纤维增强树脂基复合材料孔隙率检测方法的分析比较 总被引:2,自引:0,他引:2
碳纤维增强树脂基复合材料生产过程中会产生孔隙的缺陷,孔隙会对性能造成影响,故需要对孔隙含量进行标定。以碳纤维增强双马酰亚胺树脂为研究对象,分别采用密度法、显微照相法、超声检测法、高精度X射线数字成像法等4种方法,对热压罐和微波固化成型法制备的层压板孔隙缺陷进行检测,并计算其孔隙率。研究结果表明,显微照相法、高精度X射线数字成像技术法测试的孔隙率接近,密度法的误差较大。 相似文献
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通过改变固化工艺制备了含孔隙的碳纤维复合材料试样,采用超声检测对试样进行了初步的孔隙检测与筛选,采用金相显微法对典型区域的孔隙率、孔隙分布和形貌特征进行统计。实验结果表明,固化压力不足和袋内真空不合适会引起复合材料内部孔隙的产生,且孔隙的分布存在必然性和随机性,孔隙形貌与孔隙率存在一定的联系。 相似文献
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复合材料孔隙含量超声检测系统的设计研究 总被引:1,自引:1,他引:0
本文结合碳纤维复合材料内部孔隙含量的超声检测理论模型,阐述了计算机控制超声检测系统数据采集和数据处理的原理和实施方法.重点对数字超声卡的操作、时域波形信号的处理、复合材料孔隙率的C扫描成像显示以及直方图分析等关键问题进行分析研究,开发相应的软件应用模块,构建合适的自动化超声检测系统,以满足实际工程中超声检测的要求. 相似文献
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提出了一种基于显微CT技术的碳纤维复合材料体孔隙率测量的新方法,分析了采用显微CT技术测量孔隙率的实验原理,对实验结果进行了图像处理,并统计体孔隙率。实验结果表明,显微CT技术是一种行之有效的碳纤维复合材料体孔隙率测量技术,通过图像灰度进行阈值分割可以清晰地分辨材料内部基体与孔隙,且测量过程中应选择足够大的试样体积,测量值才能真实反映材料内部的体孔隙率。 相似文献
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基于超声的碳纤维复合材料孔隙率表征方法对比研究 总被引:1,自引:0,他引:1
研究了超声法表征复合材料孔隙率的方法,使用频域参量非线性系数进行表征,定义了经典和改进型非线性系数表达式,分析了两种非线性系数的特点,对比讨论了两种非线性系数用于评价孔隙率的灵敏度。通过改变固化压力的方法制备了碳纤维复合材料孔隙率试样,采用金相分析统计了孔隙率,并进行了衰减与非线性系数表征孔隙率的对比研究。结果表明,改进型非线性系数效果最好,经典非线性系数次之,衰减系数效果最差。改进型非线性系数更适合表征孔隙率。 相似文献
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本文采用了两种工艺制备三维编织碳纤维增强环氧树脂基(C3D/EP)复合材料,并对其力学性能和微观结构进行了研究和分析.结果表明,孔隙对复合材料的影响较大,相对RTM工艺制备的复合材料,真空浸渍法制备的复合材料有较高的空隙率,较低的弯曲强度和弯曲模量、较好的冲击性能. 相似文献
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综述油田热注蒸汽(湿饱和蒸汽)干度测量的几种有效方法——化学化验法、热力学法和非热力学法、软测量法、光学检测法和"体积变化式"测量法,分析了各种方法及其优、缺点,并提出了体积变化式测量法应用于油田蒸汽干度的测量。 相似文献
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综述油田热注蒸汽(湿饱和蒸汽)干度测量的几种有效方法——化学化验法、热力学法和非热力学法、软测量法、光学检测法和“体积变化式”测量法,分析了各种方法及其优、缺点,并提出了体积变化式测量法应用于油田蒸汽干度的测量. 相似文献
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树脂传递模塑(RTM)成型过程中不同工艺参数对碳纤维增强树脂基复合材料(CFRP)构件质量和性能有极大影响。为了精准设计RTM成型参数,降低最终构件的孔隙缺陷含量,分析充模过程中两种尺度孔隙率的变化及在构件中的分布规律,基于PAM-RTM软件对CFRP平板模型RTM成型的充模及双尺度孔隙形成进行了仿真模拟。分析了不同树脂黏度、浇注压力对填充时间及宏观和微观孔隙分布、孔隙率的影响规律;在构件中选取了不同位置的横向轴线并对比轴上宏观/微观孔隙的含量及分布特征,分析随着距离浇注口位置变化孔隙率的变化规律。结果表明,在恒压浇注条件下,浇注压力越大,树脂黏度越小,填充时间越短;树脂黏度为0.1 Pa·s、浇注压力为1.5 MPa时,充模时间最小,为13.11 s。宏观孔隙率随浇注压力升高而减小,微观孔隙率则相反。宏观孔隙在开始填充一段时间后形成,孔隙率最终在出胶口达到最大值;微观孔隙则在填充初始阶段开始形成,孔隙率随着填充距离增加逐渐减小。3条横向轴上两种尺度孔隙率的变化趋势相近;浇注压力影响宏观孔隙开始形成的位置及微观孔隙结束形成的位置,并影响填充结束时的最大宏观孔隙率和填充开始时的最大微观孔... 相似文献
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This study investigated the deposit structure in terms of the bulk porosity for Australian bituminous coals and blends that were fired in a pilot-scale test furnace. The first part of this study estimated all the deposits bulk porosity using two indirect techniques: a density measurement technique and by scanning electron microscopy (SEM). The results showed a significant difference between the two techniques. The density measurement underestimated the bulk porosity of the deposit due to the closed pores within the deposit structure. The second part of this study proposed a novel experimental approach to measure the changes in the deposit bulk porosity at elevated temperatures using thermomechanical analysis technique (TMA). The TMA bulk porosity measurements were comparable with the SEM results. 相似文献
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选取了两种纤维非织造网布,分别在进口单向碳纤维预浸料和国产单向碳纤维预浸料层与层之间进行铺放,采用预浸料成型工艺制备不同性能的层合板,并通过测试层合板试样的力学性能和孔隙率,表明纤维非织造网布在碳纤维预浸料成型技术中的适用性。对比测试数据结果发现:纤维非织造网布经向纤维纤度、纬向纤维纤度、面密度选材合适时,在碳纤维预浸料层合板中表现出了优异的适用性;纤维非织造网布经向纤维纤度及纬向纤维纤度较小、面密度选择较大时,在碳纤维预浸料层合板中虽然也表现出良好的工艺适用性,但是碳纤维预浸料层合板的力学性能会降低,孔隙率会偏大。 相似文献
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建立了液相色谱法测定嘧霉胺悬浮剂中嘧霉胺含量的数学模型,通过对测定过程中不确定度分量来源的分析,计算了各不确定度分量,并计算出合成不确定度和扩展不确定度。同时,对测定结果进行了描述,达到了对测量不确定度合理评定的目的,反映了实验室的检测技术水平和检测设备水平。 相似文献
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Focusing the adhesive bonding of thermoset carbon fiber reinforced plastics (CFRPs) due to release agent residues on a surface pretreatment prior to the bonding process is inevitable to guarantee sufficient adhesion. Based on different material and process-related phenomena, a huge variety of parameters (e.g. treatment time) influence the treatment effectiveness. This often leads to intense parameter studies in which pretreatment methods are qualified by different mechanical tests and which require significant effort in terms of time and resources. Those qualification procedures are sometimes standardized by different and mostly company-specific standards. To increase the efficiency of this qualification process by increasing the general validity, this paper presents a comparison of different mechanical test methods (namely single lap shear test, floating roller peel test, double cantilever beam (DCB) test, and cross-tension test) in terms of their sensitivity to the detection of adhesion or delamination defects, even if they normally test different aspects of a joint. However, it could be found that the most common test – the single lap shear test – can only reveal large defect levels, while different tests, e.g. DCB test, show a good sensitivity for all investigated failures and others show intermediate performance. 相似文献
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Tuba Bahtli Derya Yesim Hopa Veysel Murat Bostanci Serife YalcinYasti 《Ceramics International》2018,44(12):13848-13851
In the present study, thermal conductivity and mechanical properties of MgO-C refractory ceramic bricks were investigated. Pyrolytic liquid and pyrolytic carbon black obtained from pyrolysis of waste tires were used as a resin and carbon source, respectively. The pyrolysis of the tires was conducted in a fixed bed reactor at the temperature of 500?°C with a 15?°C/min heating rate under nitrogen flow (0.5?lt/min). Before using in MgO-C refractory ceramic blends, pyrolytic products were purified with the acidic extraction methods which resulted in 61and 66?wt%. decreases in sulfur and ash contents in pyrolytic carbon, respectively. After this treatment of pyrolytic liquid, the sulfur content was reduced by 24?wt%. Eight different blends of MgO-C refractory ceramics consisting of different pyrolytic product contents were prepared, pressed, and tempered at 250?°C, and then characterized in terms of porosity, thermal conductivity, and density. The mechanical behavior of the samples was tested using a three-point bending test. Archimedes test was employed to determine the porosity and density. Surface properties of the bricks were analyzed by scanning electron microscopy (SEM). The obtained results were compared with a reference consisting of graphite and resin. The results revealed that mechanical and thermal properties of the developed bricks were highly sensitive to the porosity and the carbon source as well as the type of binder. 相似文献