Pitch Optimization And Strength Analysis Of Jack-Up Platform Leg

Since 21 st century, the souring number of car、ship and aircraft leads to the increase of oil demand of society. At present, the operation depth of offshore platform that our nation can design independently and has property rights is around 40 meter. However, our nation has already had the ability to manufacturing the large offshore platform, it is urgent for our nation to master the key design technology of offshore platform structure. Jack-up offshore platform is one of the most widely used offshore platform. With the development of offshore oil gas industry, our nation gradually focuses on the source in deep-sea zone,such as Yellow Sea、the East China Sea and the South China Sea. Therefore, the pile leg length of jack-up platform is also need to change. The optimization of jack-up platform trussleg is benficial to ensure the safety 、 reliability and economical efficiency of the jack-up platform.This paper mainly studied the truss leg of JU2000 E jack-up offshore plateform,discussing the influences of different conditions 、 differrent wave-current angle and different pitch to ultimate bearing capacity. Programming optimization of trussleg pitch in this paper is based on immune genetic algorithm. Analysing the section parameter influences of each component to the whole trussleg weight. After the trussleg optimization,we carry out the experiment to study the influence of pitch to the ultimate strength of trussleg. Following research work have been studied specially:1 、 Investigating the current optimization theory and strength of jack-up offshore platform leg of domestic and foreign scholars, establishing the research content and research significance.2 、 Several common optimization methods are introduced.Then the definition 、characteristics and throry of immune genetic algorithm is introduced specially.3 、 Building the ANSYS finite element model referencing the truss leg data of JU2000 E jack-up offshore platform. Selecting the proper envrionmental conditions and studying the ultimate bearing capacity under survival condition and normal operating condition,which is based on the “rules for construction and classification of mobile offshore drilling units” 2012.4、Referencing the immune genetic algorithm and adopting APDL language in ANSYS to program optimization of truss leg of jack-up offshore platform.Then analysing the change influence of section pasrameter to trussleg weight.5、Selecting three adjacent pitch from optimization results and combining numerical simulation with experimental method to analysis the influences of pitch to the leg ultimate bearing capacity. Verifying the theoretic calculation through experimental results.