Development Of A Rapid Detection System For Riser Surface Crack Defect Using ACFM

This dissertation,combining with the “Twelfth Five-year Plan” project “Marine deep water oil and gas field development project” corpus “deep-water drilling riser operations management and safety assessment technology research”,focuses on the theoretical analysis of ACFM and the prototype development.Since the current conventional single probe and array probe are lack of adaptability and have low efficiency for riser surface defect detection,chain probe was designed.The main research progress is summarized as follows:(1)Study of the Numerical Model and Experimental Validation of riser ac electromagnetic field surface defect inspectionCombined with principle of ACFM and theory of numerical calculation,numerical model of riser ac electromagnetic field surface defect inspection are presented.In order to analyze the distribution of electromagnetic field on the riser surface,extract the riser surface current density and magnetic flux density.And the experimental verification shows that the simulation results are right.(2)Design of Chain probeBased on the structure of riser characteristics,combined with the conventional probe and array probe,a kind of chain structure probe was designed.The chain structure probe greatly improves the test efficiency and adaptability to the riser.By adopting the combination of numerical analysis and experimental research method,the motivate probe influence area and probes collect range were calculated,then design and development chain probe,which can adapt to different diameter of riser and flat structure detection.(3)Study on prototype for ACFM and experimental testThe overall scheme of the riser surface defect rapid detection system was designed,and each hardware and software was optimization designed.On the basis of the hardware and software,combining chain probe,developing riser surface defect rapid detection system.Eventually,the detection of experimental prototype for defect size inversion was experimented.The results show that the riser surface defect rapid detection system can get the expected Bx and Bz result curve,and identify the crack effectively.