Date of Award

8-2011

Degree Name

MS in Mechanical Engineering

Department

Mechanical Engineering

Advisor

Joseph Mello, Andrew Davol, Tom Mase

Abstract

Structure analyses of a steel tower for Cal Poly's 3 kW small wind turbine is presented. First, some general design aspects of the wind turbine tower are discussed: types, heights, and some other factors that can be considered for the design of wind turbine tower. Then, Cal Poly's wind turbine tower design is presented, highlighting its main design features. Secondly, structure analysis for Cal Poly's wind turbine tower is discussed and presented. The loads that are specific to the wind turbine system and the tower are explained. The loads for the static analysis of the tower were calculated as well. The majority of the structure analysis of the tower was performed using the finite element method (FEM). Using Abaqus, commercial FEM software, both static and dynamic structural analyses were performed. A simplified finite element model that represents the wind turbine tower was created using beam, shell, and inertia elements. An ultimate load condition was applied to check the stress level of the tower in the static analysis. For the dynamic analysis, the frequency extraction was performed in order to obtain the natural frequencies and the mode shapes of the tower. Using the results, the response spectrum analysis and the transient dynamic analysis, which are based on the modal superposition method, were performed in order to see the structure's response for earthquakes that are likely to happen at the wind turbine installation site.

transient_x_direction.avi (110489 kB)
Result of transient analysis for the wind turbine tower (Stress in psi); earthquake input was applied in the x-direction.

transient_y_direction.avi (118702 kB)
Result of transient analysis for the wind turbine tower (Stress in psi); earthquake input was applied in the y-direction.