In-Air Tension Measurement in Cables by Analyzing the Propagation of Transverse Waves Using Distributed Fiber Optics: An Experimental and Theoretical Study
Abstract
In-Air Tension Measurement in Cables by Analyzing the Propagation of Transverse Waves Using Distributed Fiber Optics: An Experimental and Theoretical Study The ability to accurately measure the tension in cables is critical for ensuring safety and functionality in various marine engineering applications. Traditional tension measurementmethods, such as invasive load cells or integrating tension meters with shackles, often introduce complexities and potential failure points in the system. Recent advancements in non-invasive techniques, such as distributed fiber optic sensing, offer promising alternatives for tension monitoring. The proposed project includes a novel experimental approach to (a) measure tension in the cables by analyzing the propagation of transverse waves in the system using distributed fiber optics and (b) compare the measured results with theoretical calculations derived from the transverse wave equation. The specific aims of the experimental plan include (i) measuring in-air tension in the cables and comparing results against theoretical transverse wave equation, (ii) evaluating the OpticalTime Domain Reflectometer (OTDR) based distributed acoustic sensor (DAS) spatial resolution on tension measurements, and (iii) measuring segmented tension in the cables by hanging varying weights at multiple points along the cable. The experimental setup involves using two different cable types to accommodate analysis of the method s sensitivity with different cable types under similar test conditions. This will help to ensure the viability of the method independent of the cable type. The cables will be suspended, anddifferent weights will be added in a laboratory setting. Further, an Optical Time Domain Reflectometer (OTDR) based distributed acoustic sensor (DAS) will be connected to the fiber optic cable. DAS will provide direct estimates of wave speed based on time delay measurements of backscattered light and resultant distributed dynamic strain profiles, which will be used to estimate the localized tension in the cable under different conditions. A mechanical shaker will be utilized in this study to introduce transverse vibrations in the cable at different frequencies. The research results from this project could be broadly applied to many defense-relatedapplications, including marine applications that involve cables. Examples include towing, stationkeeping applications using moorings in the ocean environment, and offshore infrastructure. In addition, the proposed experimental project will help prepare the workforce for the future by broadening the research experience of an early career faculty member, engaging undergraduate and graduate students in research tasks, and disseminating research results. The proposed work will take place at the University of Maine, which is located in an EPSCoR jurisdiction. The work will also involve collaboration with an industrial collaborator, Silixa, to advance the ability to measure cable tension using distributed fiber optics. Silixa continues to develop its portfolio of distributed, end-to-end, sustainable, and high-fidelity sensing solutions, including those for harsh settings such as marine environments.
Document Details
- Document Type
- DoD Grant Award
- Publication Date
- Nov 09, 2024
- Source ID
- N000142512010
Entities
People
- Amrit Shankar Verma
Organizations
- Office of Naval Research
- United States Navy
- University of Maine System