Study Of AE Propagating Mechanism In Offshore Platform Jacket And Development Of Equipment Intelligent Spot Inspection System

Steel jacket is fundamental part of many structures, but it is inclined to fatigue crack and failure when working a long time in the condition of alternating heavy load, impact load and corrosion. On the other hand, the possibility of equipments going out of order is increased with the running time accumulated. Therefore, it is significant to conduct and strengthen the monitoring of large structures and key equipments. In this thesis, the advantages of Acoustic Emission and vibration at fault recognition, assessment and life expectancy are combined to conduct the study of AE propagating mechanism in offshore platform jacket and development of equipment intelligent spot inspection system.Part I is the study of AE propagating mechanism in offshore platform jacket, which firstly demonstrates the technological feasibility of AE to monitor security of the whole offshore platform in the view of present situation. And then, wave equation of AE propagating in hollow cylinder is obtained from the perspective of elastic wave in solid medium. Experiments of analog AE sources propagating in pipes with different types of weld, elbow and diameter-wall thickness have been completed by the help of AE acquisition system, and data obtained from multiple sensors in different locations has been processed to extract characteristic parameters. By the end of this part, the effect of structural attributes of tubes on AE wave propagation has been summarized according to the comparation.Partâ…¡is the development of equipment intelligent spot inspection system which makes use of the accountability of vibration test technology, incorporates equipments maintenance and fault management, and is an object-oriented health monitoring and comprehensive application platform. A hot oil pump diagnosis has been successfully performed by the practice of equipment intelligent spot inspection system in atmospheric and vacuum distillation unit of oil refining industry, with precise fault location, immediate failure reason judgment and scientific damage evaluation. At last, fluid dynamic principle which leads to breakdown has been explained theoretically and practically.