Numerical and experimental analysis of the parameters affecting the distortion phenomenon in the welding of wind turbine tower flange

Abstract

In order to facilitate the transportation of the wind turbine tower, the tower is made of several separate parts and they are flanged to each other and fixed by the welding process. An unwanted consequence in the welding process is the distortion caused by the uneven distribution of heat in the flange. This consequence appears as residual stress and permanent deformations in the flange. In this research, the distortion in the welding of the wind turbine tower flange is studied. Numerical and experimental results show that the amount of heat flux has the greatest effect on flange distortion. By writing a subroutine and using repetition and conditional loops, the path of the welding nozzle is defined for the program and the amount of distortion caused by the heat distribution is predicted with appropriate accuracy. The comparison of numerical and experimental results shows that the difference of the displacement results depends on the cross-sectional area of the flange and its angular position. In the outer region of the flange, this difference is close to zero percent in all positions. In the middle areas of the cross-section in the angular position of 60 degrees, this difference is 33%, which has the lowest percentage difference compared to the positions of zero, 30 and 90 degrees. In the inner areas of the flange at an angular position of 30 degrees, the displacement difference is 14%, which is the least difference compared to other positions.