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Structural Health Monitoring of Composite Cryogenic Propellant Tanks Using Optical Fiber Sensors

使用光纤传感器对复合低温推进剂储罐进行结构健康监测

基本信息

批准号：
15360447
负责人：
TAKEDA Nobuo
金额：
$ 9.79万
依托单位：
The University of Tokyo
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (B)
财政年份：
2003
资助国家：
日本
起止时间：
2003 至 2005
项目状态：
已结题

来源：
https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-15360447/
关键词：
composite materials cryogenic temperature structural health monitoring optical fiber FBG sensor reusable launch vehicle strain transverse crack

项目摘要

A reusable launch vehicle is attracting much interest as one of promising future space transportation systems. Advanced composite cryogenic tanks are necessary to achieve an affordable light-weight vehicle. It is highly demanded to establish the structural integrity and reliability of such composite tanks because failure mechanisms of composite tanks are very complicated and are not well understood. The purpose of the present study is to establish a real-time health-monitoring technology to continuously monitor the strains and temperatures using optical fiber sensors embedded in composite cryogenic tanks.First, we adhered FBG (fiber Bragg grating) sensors on CFRP tanks in an experimental reusable launch vehicle, and measured the strains and temperatures in real time using a telemetry system during a launch-return cycle. The validity of the measuring method was proven and some fundamental problems were clarified.Then, we embedded several FBG sensors in filament-wound CFRP tanks. Small-diameter optical fibers (52 μm in diameter including the coating) were used to avoid the strength reduction due to the embedment. A new FBG temperature sensor was proposed to distinguish the temperature and the mechanical strain. An optimum measurement procedure was studied to obtain reliable strains and temperatures through comparison between experiments and theoretical prediction. Continuous monitoring was conducted during the entire fabrication cycle of filament-wound CFRP tanks. Effects of various fabrication conditions on thermal residual strains were studied. Detection of transverse cracks was also successfully made during the pressuring stage of CFRP tanks through the measurement of FBG reflection spectra.

可重复使用的运载火箭作为一种有前途的未来空间运输系统正引起人们的广泛关注。先进的复合低温油箱是实现负担得起的轻型车辆所必需的。由于复合材料储罐的破坏机理非常复杂，目前对其破坏机理的认识还不十分清楚，因此对其结构完整性和可靠性的建立提出了很高的要求。本研究的目的是利用光纤传感器嵌入复合材料低温储罐，建立一种连续监测应变和温度的实时健康监测技术。首先，我们将FBG（光纤布拉格光栅）传感器粘附在可重复使用的实验运载火箭的CFRP罐上，并在发射-返回周期中使用遥测系统实时测量应变和温度。证明了测量方法的有效性，并澄清了一些基本问题。然后，我们将几个FBG传感器嵌入长丝缠绕的CFRP罐中。采用小直径光纤（含涂层直径52 μm），避免了埋入造成的强度降低。提出了一种用于区分温度和机械应变的新型光纤光栅温度传感器。通过实验与理论预测的比较，研究了一种最佳的测量方法，以获得可靠的应变和温度。在纤维缠绕CFRP储罐的整个制造周期内进行连续监测。研究了不同工艺条件对热残余应变的影响。通过测量光纤光栅反射光谱，成功地检测了CFRP储罐受压阶段的横向裂纹。