Abstract: In order to carry out a precise and high-reliability design for the main shaft of MW wind turbine, a strength analysis and optimization method was proposed based on WorkBench. Firstly,The finite element model of main shaft with accessories was established, a lamina model was used to simulate bearing, and the ultimate strength and fatigue strength of the main shaft were calculated according to IEC standard. Then the relevant design variables were defined and parameterized according to the hot spot's location, and the response surfaces model were built and analyzed by using the DOE method of LHS. To minimize the weight and equivalent stress, a multi-objective optimization algorithm was used to optimize and the results were verified. The results show that the mass of main shaft is reduced by 2%after optimization, the maximum stress is reduced by 8%, and the safety margin of fatigue increased by 16.56%.The reliability and economy of main shaft have been improved.

Key words: strength of main shaft;finite element method(FEM);response surface method;multi-objective optimization