Optical fiber strain distribution sensors have become an excellent tool for Structural Health Monitoring (SHM). However, the fiber’s fragility and the time-consuming installation process have slowed down the technology’s broad application. In this study, we embedded optical fibers with textiles, allowing a much faster installation process and the ability to design specific sensor patterns for multiaxial sensing. Specifically, the fiber attached to the textile was embedded, forming a rosette configuration. The textile was bonded to an aluminum cantilever and subjected to different loads. The strain distribution from the optic fiber was measured using an Optical Frequency Domain Reflectometry (OFDR) instrument. The fiber sensor response was compared with Strain Gauges to determine the reliability of the fiber sensor.

This paper designed and fabricated a distributed fiber optic sensing textile for a composite bridge's structural health monitoring (SHM). Based on the Brillouin optical time-domain analyzer (BOTDA), the sensing textile can achieve the resolution of 1m distributed sensing ability. Unlike electrical sensors, fiber sensing systems enjoy the advantages of resistance to electromagnetic interference, survivability withstanding harsh environments, and can interrogation over kilometers. The embroidery machine from Saint-Gobain embedded the fiber system into the textile material. We have designed a U-shape fiber sensing structure including two arms of 22m each. Each arm can be used as a distributed sensing section. Embedded fiber optic sensing textile would result in reduced installation time, which lowers the labor cost and the work stoppage cost, which can be substantial for certain applications like long-range monitoring. Also, textile provides additional protection and allows the design of different layout patterns to accommodate the requirements of a project. The fiber sensing system was installed inside the girder before the bridge was built. We investigated a novel installation method using slides moving inside the girder and epoxy was applied to fix the sensing textile on the bottom side of the girders. The sensing system was tested after the bridge was built and demonstrated the feasibility of distributed fiber sensing system for monitoring composite bridges. The results indicated the potential of distributed fiber sensing systems in structural health monitoring and provide a solution of small size, low cost, high durability fiber sensing system.

Hand gesture monitoring has aroused more and more interest with the development of emerging virtual reality technologies. High precision and resolution are needed for more accurate gesture simulation. Gesture acquisition can be obtained by different sensing technologies including elastomers, mark-tracking technology, and fiber-opticbased sensors. Among these mechanisms, fiber-optic sensors have their unique advantages due to their small size and high accuracy. Fiber Bragg gratings (FBGs) based fiber-optic sensor was commonly used to monitor the bending of joints of the finger. However, FBG arrays can only measure specific points therefore the pattern design and the choice of the location around the joints could be an issue. In this paper, we reported a distributed fiber-optic sensing system. Optical Frequency Domain Reflectometry (OFDR) technology was used to realize the distributed strain monitor along the whole finger. A pattern of straight lines was evaluated on the index finger and the real-time strain change can be monitored. Through the real-time strain response, this system was able to provide accurate strain data according to different gestures of fingers.

Fiber optic sensors are useful for Structural Health Monitoring (SHM) as they can sense environmental change and can react to external stimuli such as mechanical and thermal changes. Embedding Fiber Optic Sensors (FOS) in textiles provides some rigidity to the sensing mechanism as they can be fully integrated with the structures. Additionally, textiles with fiber sensors reduce the overall installation cost. Previously reported fiber optic sensors for traffic monitoring were not fully integrated with infrastructure and some sensors were discretely placed in the structure which prevents continuous data collection process along the entire fiber optic cable. In this study, distributed fiber optic sensor embedded in smart textile with a length of about 28m is presented and installed in a pedestrian bridge located at the University of Massachusetts Lowell with the objective of detecting vibration generated by pedestrians as they walk on the bridge. This paper demonstrates the load change variations in terms of corresponding strain change using Optical Frequency Domain Reflectometry (OFDR). The length of the test was approximately 2.5 hours, and strain changes were recorded at a 30-minute interval. During the test, for minimum traffic on the bridge at the testing time, the recorded strain value was around 16.2με. For larger loads, 2 people walking on top of the textile induced a larger strain change which the record value was 371.2με. Based on the load of the bridge, strain changes results depict that higher loads results in higher strain change and vice versa. This type of distributed fiber optic sensor can be used for the application of real-time traffic monitoring as well as to continuously monitor the structure status of the infrastructure.

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