The Dynamic Characteristics Analysis Of Self-elevating Platform

Offshore platform plays a key role in the process of oil exploration and exploitation. Forall kinds of offshore platform, jack-up platform occupies an important position. Especially inChina’s vast sea, jack-up platform is more widely used because of its good mobility, currentlyin a large service number. Jack-up platform can be used as drilling, work over and productionplatform, and has become a research focus in ship and ocean engineering recent years.The present paper mainly studies the following works:(1)A3-D solid modeling of in service certain jack-up drilling platform is created.Because this paper mainly studies the dynamic characteristics of jack-up platform, theplatform model has been simplified, the pipe element and beam element are used in theprocess of finite element modeling.(2)According to the environmental data acquired from the sea area that the platformworked, the two load cases, namely storm deposit and in working, acted on the platform arecalculated, and systematic transient response of the offshore platform excited by complexloading are studied, displacement nephogram of the overall structure in the time pot whichtaking place the max displacement caused by the transient stochastic load is obtained, twokinds of operating modes are analyzed and compared.(3)In the condition of the static analysis satisfying the requirements of structural strength,using finite element analysis software ANSYS, dynamics analysis are conducted for theoverall platform structure. Natural frequencies and mode shapes of the target platform areobtained by the modal analysis; and harmonic response analysis verifies the platform of thesteady state response, which is consistent with the expected results; finally JONSWAP wavespectrum are selected as a random wave load, the spectral analysis are studied for overallstructure of the platform using the ANSYS spectrum analysis of power spectral density(PSD).