Radio-Optic Method for Measuring Relative Motion

这个小企业创新研究第一阶段项目将研究一种新的方法来测量结构和它嵌入的介质之间的相对运动（位移和速度），当系统受到冲击载荷时，如地震。在结构-介质界面处的行为的复杂性在部分或全部嵌入介质中的人造结构的设计和分析中构成了很大的不确定性来源。所提出的方法涉及使用封装和准直的放射性同位素源位于介质中的结构-介质界面附近和嵌入在结构中的塑料反射纤维阵列。当光源和光纤相对于彼此移动时，准直的光源光束穿透中间材料并扫过光纤阵列，从而在不同的时间暴露不同的光纤。源（介质）相对于纤维（结构）的位移和速度可以由纤维计数率时间历程确定。所提出的方法的主要特点包括：该仪器最大限度地减少了界面处的运动干扰;光纤可以制成带状，保持光纤间的配准，但灵活和坚固;该系统可以实现高空间分辨率和高数据收集速率。第一阶段将涉及实验室系统的设计，建模和实验测试，以证明原理。将在第二阶段开发和广泛测试实地评价工具。

This Small Business Innovation Research Phase I project will investigate a novel means of measuring the relative motion (displacement and velocity) between a structure and the medium in which it is embedded when the system is subjected to shock loads, such as those from earthquakes. The complexity of the behavior at the structure-medium interface poses a large source of uncertainty in design and analysis of man-made structures that are partially or totally embedded in a medium. The proposed method involves the use of an encapsulated and collimated radioisotope source located in the medium near the structure-medium interface and an array of plastic scintillating fibers embedded in the structure. As the source and fibers move relative to each other, the collimated source beam penetrates the intervening material and sweeps across the fiber array, exposing different fibers at different times. The displacement and velocity of the source (medium) relative to the fibers (structure) can be determined from the fiber count-rate time histories. Key features of the proposed approach include: the instrument minimizes interference with the motion at the interface; the fibers can be fabricated into ribbons, which maintain inter-fiber registration but are flexible and rugged; and the system can achieve high spatial resolution and high data collection rates. Phase I will involve design, modeling, and experimental testing of a laboratory system, in order to demonstrate proof-of-principle. Instruments for field evaluation would be developed and extensively tested in Phase II.