SBIR Phase I: Optical Fiber Sensor for Relative Humidity

这个小型企业创新研究第一阶段项目建议开发一种离散的多点可嵌入光纤传感器，用于监测混凝土结构内的相对湿度。相对湿度是影响一些与土木结构退化有关的进程的主要因素。湿度本身并不会使混凝土退化，但它确实会促进二氧化碳和氯离子等最终导致加速腐蚀的介质的作用。提出的传感器可以嵌入到结构中以提供实时数据，并且可以进行定制设计，以在整个光纤长度上实现高达3 mm的空间分辨率。该设备使用荧光包层光纤，该光纤具有依赖于相对湿度的光谱响应，并且可以制造来感测多个同时参数，如氯离子和pH。目前，湿度测量是以半破坏性的方式使用单点传感器实现的。与现有设备不同，提出的传感器可以在光纤长度沿线的多个点以非破坏性的方式提供数据。据估计，美国修复和更换混凝土桥梁的成本超过200亿美元，并以每年5亿美元的速度增加。一旦得到证实，它将在大气科学和土壤湿度监测中得到应用，以优化培养物的灌溉。

This Small Business Innovation Research Phase I project proposes to develop a discrete multi-point embeddable optical fiber sensor to monitor relative humidity inside concrete structures. Relative humidity is a major factor that affects a number of processes related to the deterioration of civil structures. Humidity alone does not degrade concrete, however it does promote the action of agents that are ultimately responsible for accelerated corrosion, e.g., carbon dioxide and chloride ions. The proposed sensor can be embedded inside a structure to provide real-time data and can be custom designed to achieve a spatial resolution of up to 3 mm over the entire fiber length. This device uses a fluorescent cladding fiber that has a spectroscopic response dependent on relative humidity and can be manufactured to sense multiple simultaneous parameters such aschloride ions and pH.Currently, humidity measurements are achieved today with single point sensors in a semi-destructive fashion. Unlike existing devices, the proposed sensor can provide data at several points along the fiber length in a non-destructive fashion. It has been estimated that the cost of repairing and replacing concrete bridges in the United States is more than $20 billion and increases at an annual rate of $500 million. Once demonstrated, it will have applications in atmospheric sciences and in the monitoring of soil humidity to optimize the irrigation of cultures.