| With the urgent need of the energy, the oil industry plays a more important role and has agreater demand in energy, which puts forward higher requirements for the design andconstruction as well as the safety. As the depths, the platform working in, are different but therelative position between the platform and the horizontal plane is almost unchanged, theplatform and the spud legs will fluctuate in a high-frequency. At above process, the platformmay be affected by wind, wave, current, earthquake and other factors. Especially, the platform,which can be regarded as a cantilever beam with large mass, will vibrate strongly when it iselevated to a certain height, and it is quite dangerous. Therefore, it is necessary to analyze thestrength for every part and the overall stability of the platform during the installation processunder the external load.In this paper, the research is supported by "the300ft jack-up drilling platform’’, which isthe first jack-up drilling platform with independent intellectual property right owned byDalian Shipbuilding Industry. The objective of this study is to ensure the development and thesafety of the jack-up drilling platform. The main works are following:(1) Modal analysis and response analysis of the jack-up drilling platformFirstly, the natural characteristics of the structure are analyzed and the equivalentstiffness is determined reasonably based on the simplified platform model. Then the naturalcharacteristics of the typical local structure in the main hull bottom of the platform areanalyzed and harmonic response analysis is carried out.(2) Seismic dynamic characteristics analysis of jack-up drilling platformThe seismic condition is analyzed with Time history analysis method, the responsespectrum analysis method and the random vibration analysis method, and also thecorresponding conclusion.(3) Vortex induced vibration (viv) response analysis of the jack-up drilling platformFirstly, the numerical simulation using the ALE method validates the feasibility of thecylinders by the LS-DYNA engineering software. Then the vortex shedding from the spudlegs is simulated at two design conditions with different flow velocities. Finally, the Vortexinduced vibration is analyzed to carry out the similarities and differences between twoconditions.It is quite dangerous for the jack-up platform in standing state, especially when the leg isinstalled at the highest point. So the security analysis of the platform is very necessary, which can provide technical support for Chinese design and construction of high level large-scalejack-up drilling platform. |
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