Pipeline deformation monitoring using distributed fiber optical sensor

Deformation of long distance pipeline takes place more easily under the various adverse factors such as freezing-thaw and earthquake, and oil and gas often leak from the broken pipeline once the deformation has exceeded a previously established threshold. In order to solve the hot issue on the pipeline deformation monitoring, this research was launched on the basis of the combination of distributed fiber optical sensor and conjugate beam method. One finite element model of a pipeline with the length of 50 m and one PVC (Polyvinyl Chloride) pipeline with the length of 4 m were constructed to validate the deformation method, respectively. The finite element pipeline model was loaded vertical displacement at different positions simultaneously, and the PVC pipeline was gradually applied different level of loads at the midspan. In the two tests, the continuous or distributed strain data and the discrete strain data were used to calculate the deformation of the pipeline based on the conjugate beam method. In order to validate the deformation monitoring method, a comparison between the displacement curve calculated by the distributed strain data and that calculated by the discrete strain data was conducted. The results of the two tests indicate that the deformation of the pipeline can be well monitored and the method can be applied to the field applications.