The Vertical Load Identification Method of the Wind Turbine Support Structure

Abstract

From the basic equation of dynamics, the precise expression of the relationship ,which is between the horizontal natural frequency and pressure load of the cantilever beam with quality attached to the free end subjecting to vertical pressures, is obtained. The approximate expression derives from the variational method. By comparing the precise numerical solution and the approximate solution of the cantilever beam with quality attached to the free end and subjecting to the vertical pressures, the conclusion of approximate linear relationship that is between the square of the natural frequency and axial force of the cantilever beam with quality attached to the free end subjecting to the vertical pressures is got. Through the comparing of theoretical results and finite element solutions, the difference between the approximate solution and the precise numerical solution is small, which can meet the requirements of accuracy on engineering. On this basis, as long as the natural frequencies of the structure at two load conditions are measured by experimental methods, elastic buckling load of the compressed beam can be identified. So the no damage test method to identify the elastic buckling load of the structures is given.