共查询到20条相似文献,搜索用时 140 毫秒
1.
在树脂基复合材料的成型工艺中大多涉及到树脂的流动过程, 而树脂压力是反映这一过程的重要参数, 监测成型过程中树脂压力的变化可以为工艺参数的选择和构件质量的控制提供指导。本文中针对热压工艺, 根据液体传压原理和特点, 自行研制了复合材料成型过程树脂压力测试系统, 对系统的精度和动态响应性能进行了研究, 并以该系统为测试手段, 初步研究了玻璃纤维单向层板中树脂压力的变化规律。结果表明, 该系统具有准确度高和动态响应敏感的特点, 满足热压成型过程树脂压力的测试要求, 为研究工艺过程树脂流动行为提供了有力的测试与验证手段。 相似文献
2.
3.
4.
5.
6.
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
7.
8.
9.
10.
本文以2400tex无捻玻璃纤维粗纱为原料,在SGA598型三维织机上制备出一种三维浅交弯联机织复合材料预制体,以环氧树脂E51和固化剂聚醚胺WHR-H023以质量比3∶1的比例组成树脂体系,并将经过表面处理的预制体与树脂基体以质量比1∶1的比例通过手糊的方式复合成型。复合材料固化过程分别使用传统热固化、真空条件下热固化和微波固化三种方式进行,制备出三维浅交弯联机织复合材料。分别考察复合材料在热定型过程中的温度变化情况,复合材料的弯曲力学性能及破坏断面,比较三种方法对复合材料性能的影响。结果表明:采用微波固化方式对复合材料进行复合成型,其在升温速度、弯曲性能和纤维与树脂间的界面性能等方面均明显好于真空固化和热固化等方式。 相似文献
11.
12.
研究了一种新型的自参考型光纤固化传感器,用于环氧树脂固化过程的实时监测。用光纤芯折射率为1.558的多模光纤制成端面反射型折射率传感器,利用环氧树脂的折射率与固化度之间的对应关系,通过实时测量环氧树脂的折射率进行固化监测。在固化过程中,当环氧树脂的折射率变化到与光纤芯的折射率相等时,传感界面的反射信号为零,传感器可对零点偏置和灵敏系数进行校准,在此后的固化过程中,传感器能够定量地测量环氧树脂的固化度。在用多个传感器对树脂内不同部位的固化过程同时进行监测的场合,各传感器经实时自参考校准后,可根据各自的灵敏系数对输出信号统一定标,从而可以相互比较,实时地反映不同部位的固化反应过程之间的差异。 相似文献
13.
14.
A refractometric sensor based on a phase-shifted long-period fiber grating written by electric-arc discharges is presented. Transmission and reflective configurations for refractive index measurements are studied. It is observed that the reflective topology permits better performance compared with the transmission one, which is the approach normally utilized in the context of long-period fiber sensing. The resolution achieved in the measurement of refractive index enables the application of this sensing head structure in demanding situations, such as the measurement of the level of salinity of water. 相似文献
15.
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
16.
A simple fiber-optic sensor based on Fabry-Perot interference for refractive index measurement of optical glass is investigated both theoretically and experimentally. A broadband light source is coupled into an extrinsic fiber Fabry-Perot cavity formed by the surfaces of a sensing fiber end and the measured sample. The interference signals from the cavity are reflected back into the same fiber. The refractive index of the sample can be obtained by measuring the contrast of the interference fringes. The experimental data meet with the theoretical values very well. The proposed technique is a new method for glass refractive index measurement with a simple, solid, and compact structure. 相似文献
17.
A method for producing uniformly thinned (etched) optical fibers is described, which can also be employed to etch optical fibers containing a Bragg grating (FBG) uniformly for evanescent-field-based sensing and other applications. Through a simple modification of this method, the fabrication of phase-shifted FBGs based on uneven etching is also shown. The critical role of how a fiber is secured is shown, and the success of the method is illustrated, by differential interference contrast microscopy images of uniformly etched FBGs. An etched FBG sensor for the monitoring of the refractive index of different glycerin solutions is demonstrated. 相似文献
18.
针对提高光纤光栅折射率传感器抗干扰能力以及增加反射率的需求,本文提出了一种基于Fabry-Perot腔的保偏微结构光纤(PM-MOF)布拉格光栅折射率传感器.根据传榆矩阵法和有限元方法,分析了微结构光纤光栅F-P腔中被测物折射率与F-P腔反射谱中两个偏振模谐振波长差的关系,在此基础上讨论了中心孔直径、F-P腔长度等参数对传输特性的影响.研究结果表明,随着空气孔中填充物折射率的增加,保偏微结构光纤光栅F-P腔的两个偏振态的谐振波长差将逐渐减小;F-P腔的干涉作用使反射率较单个光栅有很大提高,便于长距离传输和实时解调;两个偏振模对外界干扰具有相似的响应,因此该传感器具有更强的抗干扰能力.本文研究结果为保偏微结构光纤光栅在折射率传感器及其生物传感器方面的应用提供了理论依据. 相似文献
19.
A simple fiber sensor capable of simultaneous measurement of liquid level and refractive index (RI) is proposed and experimentally demonstrated. The sensing head is an all-fiber modal interferometer manufactured by splicing an uncoated single-mode fiber with two short sections of multimode fiber. The interference pattern experiences blue shift along with an increase of axial strain and surrounding RI. Owing to the participation of multiple cladding modes with different sensitivities, the height and RI of the liquid could be simultaneously measured by monitoring two dips of the transmission spectrum. Experimental results show that the liquid level and RI sensitivities of the two dips are 245.7 pm/mm, ?38 nm/RI unit (RIU), and 223.7 pm/mm, ?62 nm/RIU, respectively. The approach has distinctive advantages of easy fabrication, low cost, and high sensitivity for liquid level detection with the capability of distinguishing the RI variation simultaneously. 相似文献
20.
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