MS&P: Optical Fiber Sensors for In-Situ Temperature and Strain Measurements in Composite

多发性硬化症

• 批准号: 9202961
• 负责人: Theodore Morse
• 金额: $ 43万
• 依托单位: Brown University
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 1992
• 资助国家: 美国
• 起止时间: 1992-09-15 至 1996-02-29
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=9202961&HistoricalAwards=false
• 关键词: MS& Optical; Fiber; Sensors; Situ

Optical fiber sensors will be developed for applications in composite materials that are processed at high-temperatures (1000oC). Specifically, novel optical fibers will be used for two types of in-situ measurements: temperature and stain. Temperature sensors will be synthesized with rare-earth dopants that will permit spatially resolved temperature measurements in the range of 500- 1200oC. Strain sensors based on Fabry-Perot gratings and using optical time domain reflectometry will both be investigated. The temperature and strain sensors that are developed will be incorporated in fiber-reinforced, ceramic and intermetallic matrix composites that will be produced by chemical vapor infiltration (CVI). Because these materials already contain fibers, the incorporation of additional optical fiber sensors will not significantly perturb the microstructure. A variety of advanced, thermal gradient CVI processes are currently being developed, and the optical fiber sensors that will be developed as part of this program will make it possible to monitor temperature gradients during processing. A relatively simple thermal gradient CVI system will be used to make in- situ optical fiber temperature measurements during composite fabrication. The microstructure of these materials will also be characterized quantitatively, and a numerical model of the infiltration process will be developed to analyze both the temperature gradients and the microstructure evolution. Comparisons between the modeling calculations and the experimental measurements will provide insight into the infiltration process, and demonstrate the potential for using optical fiber temperature sensors. The strain sensors will provide measurements during processing, and more importantly, they will make it possible to measure strain when the composite is in use. These in-situ strain measurements offer a novel method to study the stress-strain behavior of the material. In brittle matrix composites, the matrix phase typically begins to microcrack long before the material fails, thus these in-situ strain measurements are particularly important because it will be possible to monitor the degradation of these materials before macroscopic failure actually occurs.

光纤传感器将成为 开发用于 复合材料， 高温处理 （1000oC）。 具体来说，小说 光纤将用于两个 现场测量类型： 温度和染色。 温度 传感器将与 稀土掺杂剂， 空间分辨温度 测量范围为500- 1200oC。 应变传感器基于 法布里-珀罗光栅及其应用 光时域反射技术 都将被调查。 的 温度和应变传感器， 将被纳入 在纤维增强、陶瓷和 金属间基复合材料， 将由化学蒸汽产生 渗透（CVI）。 因为这些 材料已经含有纤维， 并入额外 光纤传感器不会 严重扰乱了 微观结构 各种 先进的热梯度CVI 目前， 开发的，光纤 传感器将被开发为 这个项目的一部分将使它 可监测温度 加工过程中的梯度。 一 相对简单的热梯度 CVI系统将用于制造- 光纤原位温度 合成过程中的测量 制造。 的微观结构 这些材料也将 定量表征，和 入渗数值模型 将开发一个过程来分析 温度梯度和 微观结构的演变。 模型之间的比较 计算和实验 测量将提供洞察力 渗透过程， 展示了使用 光纤温度传感器 应变传感器将提供 加工过程中的测量，以及 更重要的是，他们会成功的 可以测量应变时， 复合材料正在使用中。 这些就地 应变测量提供了一种新的 应力应变研究方法 材料的行为。 在 脆性基复合材料 基质相通常开始 微裂纹早在材料 失败，因此这些原位应变 测量特别 重要的是， 可以监测降解 这些材料之前， 实际上发生了宏观破坏。