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本文论述了应用光纤传感器对RTM的固化过程及制品疲劳损伤进行监测的技术方法。研究中 ,采用的增强材料为玻璃布 ,环氧树脂作基体。应用两种光纤应变传感器进行应变测定 ,一种是Bragg光栅 (FBG)传感器 ;另一种是外置式Fabry -perot干涉型 (EFPI)传感器。传感器埋入方向与树脂流动方向垂直或平行。研究结果表明 :垂直埋入的FBG传感器在被固化树脂约束前 ,复观性差。另外 ,还发现FBG和EFPI传感器在冷态下具有良好的准确性。平行埋入的FBG传感器在模塑工艺中表现出良好的复观性。标距为 1mm和 4mm的传感器的应变现象不同。上述结果说明 ,将光纤传感器埋入FRP中 ,光纤传感器的埋入结构和标距对应变测量的精度有影响。利用埋入的光纤传感器进行固化监测 ,然后再循环加载试验 ,测定其内应变。循环加载试验的结果是用FBG传感器测得的应变与粘贴应变片测得的应变具有良好的一致性。本项研究得出的结论是 :通过埋入FBG应变传感器可对RTM成型FRP工艺过程和使用过程中的内应变进行有效地监测。
This paper discusses the application of optical fiber sensor RTM curing process and product fatigue damage monitoring method. In the study, the reinforcing material used was glass cloth and epoxy resin as matrix. Two types of fiber strain sensors are used for strain measurement, one is a Bragg grating (FBG) sensor and the other is an external Fabry-perot interference type (EFPI) sensor. Sensor embedding direction and resin flow direction perpendicular or parallel. The results show that the vertically buried FBG sensor has poor repeatability before being restrained by the cured resin. In addition, FBG and EFPI sensors were also found to have good accuracy in cold conditions. FBG sensors embedded in parallel exhibit good reproducibility in the molding process. Sensors with gauge distances of 1 mm and 4 mm have different strains. The above results show that when the optical fiber sensor is embedded in the FRP, the embedded structure of the optical fiber sensor and the gauge length affect the accuracy of the strain measurement. The embedded optical fiber sensor was used for curing monitoring, and then the cyclic loading test was carried out to measure the internal strain. The result of the cyclic loading test is that the strain measured by the FBG sensor is in good agreement with the strain measured by the adhesive strain gauge. The conclusion of this study is that the FBG strain sensor embedded can effectively monitor the RTM-molded FRP process and the internal strain during use.