Diagnosis And Experimental Study Of FBG Sensor Based On Vessel Monitoring System

Under the complicated and volatile marine environment,there are various factors that can lead to vessel structural damage.Therefore,the vessel structure safety monitoring system is designed to prevent ships from this,by means of long-term monitoring and real-time assessment of the vessel structure.However,the system is in the primary stage of development,there are many problems need to be solved in engineering application.The fiber bragg grating(FBG)strain sensors are extensively used in the monitoring system.FBG strain sensors are more mature technology.However,there still exit great hidden dangers in the actual application,due to the imperfection of its industry standards and the lack of research on its fault diagnosis.The applicability and reliability are in urgent need in the vessel structure safety monitoring system.Thus,this paper studies the characteristics of the FBG strain sensor,the fault diagnostic system and the temperature compensation algorithm.The main contents are as follows:First of all,the paper studies the characteristics of the FBG strain sensor.Experiments on different kinds of sensors are carried out to test their performance.According to the results,highly-reliable sensors are chosen for the vessel structure safety monitoring system because of their better applicability.Combined with the multiplexing method of sensor,a hybrid sensor network applied to the vessel structure safety monitoring system is put forward.Secondly,after studying the fault diagnosis of marine FBG strain sensors,this paper puts forward different fault types that may occur during the voyage,and analyzes their causes,then establishes the fault library of FBG strain sensor.On this basis,a practical scheme for sensor fault diagnosis is put forward and has been tested by plenty of experiments.Furthermore,it is integrated into the monitoring system and realized by relevant software program.Finally,the paper discusses on the temperature compensation method for the FBG strain sensor.Temperature and stress both can affect the sensor temperature drift,so the contrast experiments are designed.Based on BP neural network,the temperature compensation algorithm is adopted to eliminate the influence of temperature,with experiments carried out to test the accuracy and reliability.