| Deepwater floating platform, its subsidiary of mooring system and riser system form the floating production system, which is the main infrastructure of deepwater oil and gas development, and the safety deepwater floating platform is crucially important. Although it has a history of nearly three decades of deep sea oil drilling abroad and rapidly developing desgin thoeries, the safety of deep water floating platform is still at serious risk due to the harsh conditions within the deep-sea environment. Thus, in order to ensure safe operation of platform, it is important to establish a set of structural monitoring system for deep water floating platform to full-automatically monitor the marine environmental factors, key components of platform and the overall structure in all the time and in real time. The structural monitoring system not only can get hold of the safety status of structure in real time, but can also provide full-scale field test data for relevant research and valuable basis for completing related theory. With its excellent motion performance, superior dynamic stability and high efficient economic benefits, Spar platform is widely used in deepwater development. To regard the Spar platform as the research object, the structural health monitoring system design of Spar platform is intensively studied in this paper. The main contents are as follows:First of all, after the domestic and abroad accidents of floating platform are reviewed and analyzed, the main failure modes of the floating platform are summarized. Based on the analysis of the failure mode, the key monitoring parameters of the health monitoring system for Spar platform are given. On this basis, with the combination of sensor selection principle, the corresponding sensors are selected, which provides important basis for health monitoring system design of Spar platform.Secondly, against deficiencies that choosing local monitoring points currently relies on experience, an optimization method of measuring points based on vulnerability parameter is proposed in this paper. According to the characteristics of vulnerability stipulate the determination principle of vulnerability parameter, with combination of the health monitoring purpose of local structure and nature of structural vulnerability defines vulnerability parameter. On this basis, the optimization model of measuring points based on vulnerability parameter is established. And the method of solving the optimization model is given by combining with conventional computing method from criterion. Take the case study of the main structure of a Spar platform as an example. After calculating the monitoring point optimization for the local performance, the corresponding optimal points are determined.Then, based on the principle of security early warning index, combining Spar platform structure monitoring parameters and corresponding structural design specification, the safety early warning indicators of structural health monitoring for floating platform are determined. By adopting the warning threshold value method, the early warning hierarchies of structural monitoring parameters are graded and corresponding critical warning value are determined. Take a Spar platform as an example. Early warning indicators of each monitoring parameter under a100-year condition are analyzed.Finally, according to the goals of health monitoring system for Spar platform and the logical relationship between components of health monitoring system and with the design principle of structural health monitoring system for Spar platform, the health monitoring system for Spar platform is depicted, thus, overall monitoring scheme of Spar platform is presented. On account of the principle of system integration, integrated design is done in accordance with the logical relations and functions of subsystems in health monitoring system. |
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