Dynamic Characteristic Analysis Of Large Horizontal Axis Wind Turbine Tower-foundation

The wind, as clean energy, has been developed by many countries. In order to improve the output power of the wind turbine, it has been made larger which makes the size of it’s blade、tower increasing. Dynamic analysis of wind turbine is mainly study the natural characteristic of structure, the natural frequency and vibration mode of tower、foundation and tower-foundation are get by taking dynamic analysis of these structures separately. It has important theoretical value and practical significance for safety operation and optimization design of the wind turbine.This paper analyzes the domestic and foreign research present of wind turbine tower and foundation, studied the dynamic characteristics of wind turbine structure by using finite element analysis theory. And established the finite element model of a wind turbine tower-foundation based on a kind of1.5MW large-scale horizontal axis wind turbine by ANSYS software. Taking modal analysis and transient dynamic analysis of tower-foundation model by ANSYS software, analyzed the influence of foundation stiffness and stiffener on the dynamic characteristics of wind turbine tower, provide a theoretical basis for the design of the wind turbine. The main work is as follows:1. In order to consider the effect of internal flange and stiffeners on the wind turbine tower, the two internal flange which taking the connection role between segmented tower are simplified into ring stiffeners. In the progress of establish the finite element model of the tower by ANSYS. The thin walled structure like tower and blades are simulated by shell element, the stiffeners are simulated by beam element, the connection between the tower wall and stiffeners are used the method of multi-point constraints.2. Built three models with different stiffeners and get the natural frequency and vibration mode of these models by taking dynamic analysis on ANSYS.3. Consider the effect of base by building tower-foundation model with pile foundation by ANSYS. The foundation are simulated by solid element, the piles are simulated by spring element, the connection between the bottom of the wind turbine tower and foundation are used the method of multi-point constraints. And study the influence of foundation stiffness on the dynamic characteristics of tower by modal analysis of the tower-foundation model. 4. The transient response analysis of tower-foundation under seismic load is taken to study the relationship between displacement、velocity、acceleration of structure under seismic load and time.