Study On Ice Induced Vibrations Of Offshore Wind Turbine Structure In Bohai Sea

With the rapid development of offshore wind power,the exploitations of offshore wind energy resources in cold regions have attracted more and more attentions.However,accompanied with the huge wind energy reserve are the threats caused by sea ice.Therefore,ensuring a safe and continuous operation under these particular threats has become the key issue of offshore wind power development in cold regions.Based on this background,the analysis on ice induced vibration on a tripod offshore wind turbine structure installed in Bohai Sea was carried out.In the analysis,firstly,the nonlinear characteristics of the structure,i.e.having significant differences in the dynamic characteristics of the parallel structures,were accurately simulated.Secondly,reasonable calculation cases were set up according to the site conditions of sea ice.Finally,time histories of ice loads were obtained through dynamic ice load function and transient dynamic analysis were subsequently carried out.Basing on thoroughly analyses of the calculating results,an important factor that represents the interaction process between the ice and structure was established and named as the integrated control factor(IC).Furthermore,the ice induced vibration events were divided into several regions in consistence with IC.The calculating method for estimating the occurring probabilities for the regions was also given in this paper.The methods presented in this paper will provide important references for the judgements and evaluations on the ice induced vibrations of offshore wind turbine structures in Bohai Sea.