Study On The Key Technologies Of Vibration Flaw Detection In The Oil Pipeline

The pipeline leak detection technology occupies an important position in the use of thepipeline safety. Now the pipe laying is more complex, widely distributed, long distance,which has brought many dififculties to the leakage monitoring. As the fiber Bragg gratingsensors have the incomparable advantage of mechanical, electrical type sensors. In the thesis,focus on ifber grating vibration acceleration sensors and fiber Bragg grating sensors in thepipeline leak detection technology issues. Understand the current situation and developmentdirection of today’s oil pipeline leak detection situation. Mainly from the fiber Bragg gratingsensor technology, developed a new type of ifber Bragg grating vibration acceleration sensor,and study on several key issues in the pipeline vibration flaw detection technology.Fist, the thesis pushed to the basic formula of the fiber grating from the fiber gratingwaveguide structure. Analyzed the basic optical parameters of the ifber grating, establishedthe basic model of the ifber Bragg grating temperature, stress and strain sensing, thistheoretical basis for the subsequent design of fiber Bragg grating sensors.Then analyzed the pipe vibration caused by the mining, drilling and other acts ofvandalism, birefly addressed the propagation mechanism of the excitation signal and vibrationsignal, established the mathematical model of the frequency and amplitude of the vibrationsignal generated by the excitation source characteristics, theoretical analysis of the vibrationcharacteristics of the oil pipeline caused by all cases.Basis on sensing mechanism of the fiber grating, designed a drum-type skeleton basestructure of fiber Bragg grating (FBG) vibration sensor, the FBG was mounted ondouble-cylindircal ring，the structure was composition of a number of flexible sheet. And thetheoretical model on the explanations, tear down this structure of the mathematical model andconfirmed the feasibility of such a structure, in theory.Finally, basis on the model of the designed sensor, analysis of the performanceparameters of the elastic material, select the appropriate elastic mateiral processing elastic element. Packagc the processed the elastic element and the shell of vibrator. Processed sensorshell and ifber grating combined to build the expeirmental system，the analysis ofexpeirmental data to know the vibration sensor performance parameters. By the experimentsof fluid leak and instant hit shown the sensor was suitable for engineers and technicians in theJow-rfcquency (20-300Hz) vibration testing.