Stress Analysis of a 2.5 MW Wind Turbine Main Frame - A Finite Element Study

Main frame is one of the wind turbine nacelle parts, which includes critical rotating parts like the main shaft and gearbox. Main frame experiences considerable loads due to gravity and operating conditions, which are explained as 14 load cases. Force and moment components of load cases are presented in fixed main bearing coordinate. Steel S235J2 and S355J2 are used in the main frame. The main purpose of the present study is stress analysis of a 2.5 MW wind turbine. This analysis has been performed utilizing the finite element method in the Ansys workbench. Average and elemental mean stress are utilized to explain the maximum stress in load cases. These stress are modified in singular points using the Hobbacher method. The safety factor of each load case is calculated considering the maximum stress of the model after modification. Stress analysis results show the highest stress in the main frame is 141 MPa which leads to the safety factor 1.44. Design of the wind turbine main frame can be improved by considering the stress analysis result.