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设计了两种新型光纤传感器,一种是通过测量光纤末端近场模斑谱反映光纤埋置 脂折射率的变化,另一种行微弯衰减方法测量复合材料固化中铺层被压缩的进程。利用这两种传感器进行了复合材料固化监测实验,结果表明,发现光纤模斑传感器的信号可以反映树脂基体的粘度的变化历程,光纤微弯传感器的信号可以反映铺层被压缩的过程,监测这两个关键的参数变量不但有利于操作工艺的优化,而且为建立复合材料因化过程的智能化在线监控系统奠 相似文献
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无论在军事还是航空航天领域,光纤传感器都是一种极具应用前景的智能化监测手段。目前,将光纤传感器用于纤维增强树脂基复合材料固化过程的监测的研究是一个热点。但由于大多数光纤传感器监测固化过程成本较高,所以还没有被广泛的应用于实际生产当中。开发了一种新型的低成本、高灵敏度、易操作的光纤传感器用于纤维增强树脂基复合材料固化过程的在线监测。光纤传感器的设计基于光纤微弯损耗原理,其监测的直接目标参量为增强纤维所构成的网络所承担的压力变化,可以进而通过Gutowski的树脂流动/纤维变形理论间接得出对于固化过程中的几个关键参量。给出了这种压力传感器的设计制作方法,测定该种传感器在静态和动态下的压力-光损耗响应曲线,分析了该传感器对环境温度与折射率变化的响应。完成了利用微弯压力传感器进行纤维增强复合材料在热压釜中固化成型过程的在线监测实验,获得了良好的结果。 相似文献
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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。 相似文献
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复合材料固化成型工艺是影响树脂基复合材料结构性能的关键之一,因此需要针对其固化过程进行有效在线监测。本文基于压电传感器提出一种超声导波技术和机电阻抗技术相结合的树脂基复合材料固化过程监测方法,研究了超声导波能量与固化时间的关系及机电阻抗共振峰随固化时间的变化规律。研究表明,固化过程中树脂基复合材料结构的超声导波信号幅值和机电阻抗信号共振峰频率均出现先减小后增大并逐渐平稳的趋势,可以体现树脂基复合材料固化过程中的一系列变化。以监测单向碳纤维(T300)/热固性环氧树脂预浸料固化为例,验证压电传感器对复合材料固化的监测方法。T300/热固性环氧树脂复合材料在真空袋压、固化温度为120℃条件下,20 min为凝胶时间点,65 min为固化完成时间点。本研究基于压电固化过程在线监测方法为树脂基复合材料成型工艺的设计和优化提供了基础数据和技术支撑。 相似文献
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提出采用光纤微弯传感器测量复合材料固化中粘度的变化。选择了合适的光纤并进行了增敏处理。完成了不同铺层方式的复合材料固化进程的粘度测量, 并与动态介电方法的测量结果进行了比较。结果发现, 光纤微弯衰减方法对于热压情况下复合材料的固化监测是敏感的。该方法可重复性好, 可以准确给出树脂粘度最低点和固化完成点的时间, 灵敏度与光纤同增强纤维的交角有关。利用完成固化监测功能后仍具有光波导性能的已埋入光纤, 研制了两种类型的振动传感器。 相似文献
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树脂基复合材料经常与金属材料固化在一起使用。用缠绕方法制备了复合材料单向板, 将光纤布拉格光栅(FBG) 埋入复合材料与铝板之间, 监测两种不同的材料在固化过程中界面的性质, 并与复合材料内部的监测结果相比较。监测结果表明, 光纤布拉格光栅准确地监测到了复合材料固化过程的温度历程, 复合材料内部、铝板和复合材料的界面在固化过程中和固化后应变存在着明显的差异。光纤光栅传感器为两种不同材料之间的固化监测提供了工具, 对界面性质的分析提供了新方法。 相似文献
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In this work, a dual functionality fiber optic sensing system for thermoset cure monitoring has been developed and successfully tested. Principle of operation relies on the use of a standard optical fiber in single ended configuration containing a single in-fiber Bragg grating. The change in refractive index directly related to material density at fiber end and the variation in the wavelength reflected by the fiber grating have been monitored simultaneously, throughout an In-Mould curing process of an epoxy resin. A compact and low cost in-fiber dual wavelength demodulation system has been developed and experimental results demonstrate the capability to on line identify the degree of cure, gel point, residual stresses and the glass transition temperature of the cured resin. 相似文献
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A fiber optic ultrasonic system is described which monitors the cure of an epoxy resin. Ultrasound is generated using a high-power
optical fiber to deliver high-energy pulses of light to the prepared surface of an aluminum mold that contains the curing
epoxy resin. The generated ultrasound is detected using a local fiber optic ultrasound sensor embedded in the curing epoxy
resin. The system was used to measure the ultrasonic signal velocity and ultrasonic attenuation throughout the cure of a neat
epoxy resin at room temperature. Similar measurements also were performed using a piezoelectric transducer for ultrasound
generation and an embedded fiber optic sensor for detection, which provided verification of the results using the complete
fiber optic system. The complete fiber optic system demonstrated adequate sensitivity throughout the entire cure to measure
the ultrasonic signal velocity and ultrasonic attenuation. 相似文献
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The on-line cure monitoring of fiber reinforced thermosetting resin matrix composite material has been performed for improving quality and productivity during manufacturing. Since the dissipation factor measured by dielectrometry method is dependent on the degree of cure and temperature of resin, in this study, a new method to obtain the degree of cure during on-line cure monitoring for S-glass/polyester composites without temperature effect was developed by employing a combination function of the temperature and the dissipation factor. The temperature signal was measured with a K-type thermocouple and the dissipation factor signal was measured with an interdigital dielectric sensor during curing process. Then the calculated degree of cure using the measured data from dielectrometry was compared to the measured value from differential scanning calorimetry. The developed on-line cure monitoring method was applied to a 2-step cure cycle for the verification of the developed procedure. 相似文献