SBIR Phase I: Optical Fiber Sensor for Relative Humidity

这个小企业创新研究第一阶段项目建议开发一种离散多点嵌入式光纤传感器来监测混凝土结构内部的相对湿度。相对湿度是影响与土木结构恶化有关的许多过程的主要因素。湿度本身不会使混凝土降解，但它确实会促进最终加速腐蚀的物质的作用，例如二氧化碳和氯离子。所提出的传感器可以嵌入到结构中以提供实时数据，并且可以定制设计，在整个光纤长度上实现高达3毫米的空间分辨率。该设备使用荧光包层光纤，其光谱响应依赖于相对湿度，可以同时检测多个参数，如氯离子和ph。目前，湿度测量是通过半破坏性的单点传感器实现的。与现有的设备不同，所提出的传感器可以在光纤长度的几个点上以非破坏性的方式提供数据。据估计，在美国，修理和更换混凝土桥梁的费用超过200亿美元，并以每年5亿美元的速度增长。一旦证明，它将在大气科学和土壤湿度监测中得到应用，以优化栽培的灌溉。

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.