| With the rapid development of ocean economy,the application of optical fiber composite submarine cable integrated with power transmission and communication is becoming more and more extensive,and it is necessary to carry out safety monitoring.In order to make the optical fiber composite submarine cable run without fault for a long time,we can use distributed optical fiber sensing technology to monitor the strain of optical fiber in real time and get the health state of all other structures of submarine cable.This paper studies the mechanical behavior of optical fiber composite submarine cable in the process of manufacture,transportation,laying and operation.Based on the mechanical finite element theory,according to the pull and sudden large tension during the laying process of submarine cable,the tensile finite element model of single core submarine cable is established.Simulation data of stress,strain and plastic strain of each layer of submarine cable are obtained under different tensile loads.Data of each layer's structural stress and fiber strain function are obtained through processing data.The finite element model of the three-core submarine cable is established in view of the hooks,anchors and torsion conditions encountered in the laying and operation of the three-core submarine cable.The stress of each layer structure of submarine cable and fiber strain curves under different hooks and torsion velocities are obtained,and the function relationship between them is obtained by least square method.The stress and strain of each layer of submarine cable and the strain value of copper conductor,lead alloy sheath and steel wire arm during yielding time are obtained in the process of anchoring.By using the results of this study,we can calculate the stress of each layer of submarine cable and get the operation state of cable through monitoring the strain value of optical fiber,providing the basis for real-time monitoring and fault diagnosis of submarine cable. |
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