Papers by Keyword: Distributed Fiber Optic Sensor

Paper TitlePage

Authors: Li Qi Yi, Cai Fu Qian, Ke Qin Ding, Song Qiao
Abstract: A method for detecting pipeline’s deformation is presented in this paper, based on distributed fiber optic strain sensor. We simplify the pipeline and analysis it as a beam. According to beam’s geometrical relational expression, pipeline’s deflection could be calculated by using discrete strain with numerical method.
Authors: Tadahito Mizutani, Takafumi Nishi, Nobuo Takeda
Abstract: Although demand for composite structures rapidly increase due to the advantages in weight, there are few effective assessment techniques to enable the quality control and guarantee the durability. In particular, an invisible microscopic damage detection technology is highly required because damages such as transverse cracks, debondings, or delaminations can lead to the critical failure of the structures. Among many non-destructive evaluation (NDE) methods for composite structures, fiber optic sensors are especially attractive due to the high sensitivity, the lightweight, and the small size. In the current trend of the structural health monitoring technology, fiber Bragg gratings (FBG) sensors are frequently used as strain or temperature sensors, and Brillouin scattering sensors are also often used for a long distance distributed measurement. The Brillouin distributed sensors can measure strain over a distance of 10km while a spatial resolution was limited to 1m. Some novel sensing method is proposed to improve the spatial resolution. The pulse-prepump Brillouin optical time domain analysis (PPP-BOTDA) is one of the latest distributed sensing applications with a cm-order high spatial resolution. The PPP-BOTDA commercial product has the spatial resolution of 10cm, and can measure the strain with a precision of ±25og. This precision, however, can be achieved by using conventional single-mode optical fibers. In our research, small-diameter optical fibers with a cladding diameter of 40om were embedded in the CFRP laminate to avoid the deterioration of the CFRP mechanical properties. Thus, in order to verify the performance of PPP-BOTDA, the distributed strain measurement was conducted with the small-diameter optical fibers embedded in the CFRP laminate.
Authors: Guo An Wang, Hao Zhang
Abstract: For Brillouin Optical Time Domain Reflectometry (BOTDR) based distributed sensing technique, limited by 1m-order spatial resolution, it is difficult to monitor or test localized deformation, and loop installation of optical fiber sensors is a good countermeasure, In this paper, firstly, the measurement behavior and performance of loop installed optical fiber sensors is investigated experimentally, and the accuracy of BOTDR based distributed fiber optic sensors (DFOS) is evaluated. Furthermore, an experimental investigations on a steel specimen is carried out. Based on the investigations, steel structure damage identification method with no requirement for a structural Numerical Model is proposed.
Authors: Y. Zhou, Shi Jiu Jin, H. Feng, Z.M. Zeng, Z.G. Qu
Abstract: A new distributed optical fiber pipeline leakage detection technology based on Mach-Zehnder optical fiber interferometer theory is put forward. When using this technology, an optical fiber cable is laid along the pipeline. Noise from leaking point on the pipeline can be acquired by the optical fiber vibration sensor which was composed of three single mode optical fibers, thus, leakage occurred on the pipeline can be detected in real time. The detection principle and system construction are explained and in-site testing data is analyzed. With principle analysis and experimental results, it is demonstrated that the detection system’s measuring sensitivity and location accuracy for detecting leakage are high when adopting this technology.
Showing 1 to 4 of 4 Paper Titles