Study On Themechanicl Problem In The Progress Of Jack-up's Legs Concatenating Out Of Dock

Because of the increasing categories and amounts of the ocean-platform, the security of the ocean-platform has been regarded during the process of building and fixing. Especially for the jack-up, the legs have their own special installing methods. Nowadays, the common installing methods includes: Hosting craft in dock; Assemblage craft in deep water; Assemblage craft in deep water. The dangerous level of the methods which listed above is very high during the fixing process of the platform body and the pile shoe. No matter in overseas or domestic, different factories adopt their own method for the fixing process. Each methods have their own features, therefore the mechanics characteristic of each methods are different. For every appointed method, not the strength of separate component but the stability of the whole body should be calculated to the results of responses of structure acted by out-load.In the whole progress of legs concatenating, the jack-up is on a unnormal work condition. The main bady will rise up to 160 meter high when welding the last leg subsection. The whole structure will be treated as slender cantilever that the mass assemble up. The jack-up maybe create wide-range strain, sympathetic vibration, atructural damage and even turnover when it is on the loading of wind and earthquake. So it is very necessary to analyse the stability and dynamical response in this particular work condition.This dissertation is deponding on JU2000, one type of jack-up that can work on 400 feet depth of water and manufactured by Dalian Shipbuilding Industry Co., LTD. Studying on the mechanical problem in the progress of legs concatenating out of dock; Simulating the statical and dynamical loading on jack-up; Setting up stability analysis modal against overturning. Analysing the factor that affecting the stability of jack-up in the progress of legs concatenating out of dock; Using finite-element method to set up the finite-element modal of JU2000, Analysing its dynamical property in different work condition. On the basic of modal analysis; Studying the dynamical response of jack-up on the pulsating wind loading; Using the response spectrum and random vibration method to finish the dynamical property analysis on the loading of earthquake.