Fiber grating-based strain sensor array for health monitoring of pipelines

Abstract

Pipelines are one of the most important modern energy transportation methods, used especially for the transportation of certain dangerous energy media materials such as crude oil, natural gas, and chemical raw materials. New requirements have been put forward for the health monitoring and early security warning of pipelines because of the large-scale and complicated development trend of the pipe network system. To achieve an accurate assessment of the health conditions of pipeline infrastructure, obtaining as many precise operating parameters as possible, particularly at some critical parts of the pipeline, is necessary. Therefore, a novel type of fiber grating strain sensor array is proposed herein to monitor the pipeline hoop strain. The sensor utilizes fiber grating characteristics such as light weight, corrosion resistance, remote transmission, and strong environmental adaptability. The fiber containing the grating measurement points is implanted into the composite material to complete the sensitization encapsulation and protection of the bare fiber grating. The design of the sensor array fulfills the requirements for monitoring pipeline mass data, making it easy to form a pipeline health monitoring sensor network. The sensor sensitivity is researched by using a combination of theoretical and experimental analysis. A sensitivity test, as well as linearity and stability tests, are performed on the sensor. The experimental results show that the average sensitivity of the sensor is 14.86 pm/μϵ, and the error from the theoretical calculation analysis value is 8.75%. Due to its high reliability, good linear response and long-term stability, and the ability to reflect the exact strain change of the outer wall of the pipeline, the designed sensor can support longterm online pipeline monitoring. The fiber grating sensor array network has successfully realized the monitoring of the pipeline's internal operation by using external strain changes. In addition to the performance benefits, there are other merits associated with the applicability of the sensor namely simple structure, compact size, manufacturing ease, and exterior installation ease.