Department of Electrical Engineering, Princeton University, Princeton, NJ 08544, USA.
Department of Civil and Environmental Engineering, Princeton University, Princeton, NJ 08544, USA.
Sensors (Basel). 2020 Mar 3;20(5):1386. doi: 10.3390/s20051386.
Damage significantly influences response of a strain sensor only if it occurs in the proximity of the sensor. Thus, two-dimensional (2D) sensing sheets covering large areas offer reliable early-stage damage detection for structural health monitoring (SHM) applications. This paper presents a scalable sensing sheet design consisting of a dense array of thin-film resistive strain sensors. The sensing sheet is fabricated using flexible printed circuit board (Flex-PCB) manufacturing process which enables low-cost and high-volume sensors that can cover large areas. The lab tests on an aluminum beam showed the sheet has a gauge factor of 2.1 and has a low drift of 1.5 μ ϵ / d a y . The field test on a pedestrian bridge showed the sheet is sensitive enough to track strain induced by the bridge's temperature variations. The strain measured by the sheet had a root-mean-square (RMS) error of 7 μ ϵ r m s compared to a reference strain on the surface, extrapolated from fiber-optic sensors embedded within the bridge structure. The field tests on an existing crack showed that the sensing sheet can track the early-stage damage growth, where it sensed 600 μ ϵ peak strain, whereas the nearby sensors on a damage-free surface did not observe significant strain change.
只有在传感器附近发生损坏时，才会对应变传感器的响应产生显著影响。因此，二维（2D）传感片可覆盖大面积，为结构健康监测（SHM）应用提供可靠的早期损伤检测。本文提出了一种由密集的薄膜电阻应变传感器组成的可扩展传感片设计。该传感片采用柔性印刷电路板（Flex-PCB）制造工艺制造，可实现低成本、大批量生产，能够覆盖大面积。在铝梁上的实验室测试表明，该薄片的灵敏系数为 2.1，漂移低至 1.5 μϵ/天。在人行天桥上的现场测试表明，该薄片足够灵敏，可以跟踪由桥梁温度变化引起的应变。与嵌入在桥梁结构中的光纤传感器得出的表面参考应变相比，薄片测量的应变 RMS 误差为 7 μϵ r m s。在现有裂缝上的现场测试表明，传感片可以跟踪早期损伤的增长，其检测到的峰值应变为 600 μϵ，而在无损伤表面的附近传感器没有观察到明显的应变变化。
