Comprehensive performance evaluation of offshore wind turbines under complex environmental loads

Considering the structural characteristics and both internal and external excitations of offshore wind turbines, a rigid-flexible coupled multi-body dynamic model for large-scale turbines is established. A comprehensive performance evaluation method is proposed, integrating the interpretive structural modeling(ISM) technique with the analytic network process(ANP). A multi-dimensional performance evaluation framework is built, including five primary indicators and eleven secondary indicators. The ISM method is employed to analyze the interrelationships among evaluation indicators and to develop a multi-level hierarchical structure for comprehensive assessment. The ANP is then used to construct judgment matrices, supermatrices, and limit supermatrices, through which the weights of evaluation indicators are determined. Based on these results, the comprehensive performance of offshore wind turbines is quantitatively evaluated, and a comparative analysis of two turbine models is conducted. The results show that the most influential factors affecting overall performance include blade length, time-varying reliability of bearings, gear contact fatigue reliability, and unit megawatt weight. Additionally, the 5 MW wind turbine demonstrates superior comprehensive performance compared with the 6.2 MW model.