Strength analysis of girth welds of wind power towers with typical defects

Abstract

Defects such as pores, slag inclusions, and cracks account for a high proportion of the girth weld defects of wind power towers, which seriously affect the safe operation of wind power towers. Therefore, the strength analysis of the girth welds of wind power towers with typical defects has important engineering application value. Taking a 2 MW wind power tower as the research object, we used regular hollow spheres, semi-cylinders and hollow rectangles to characterize the defects. With the failure criterion based on yield strength, the strength analysis of girth weld defects with different types, sizes and locations under three ultimate load cases was carried out. The research shows that for a single spherical pore defect, with the increase of the pore radius from 2 mm to 8 mm, the maximum equivalent stress of the girth weld of the tower increases, and the closer the pore is to the inner and outer surfaces of the wind turbine tower, the greater the maximum equivalent stress is for crack defects , the maximum equivalent stress increases with the increase of the crack defect length, but when the defect length is greater than 25 mm, the maximum equivalent stress tends to decrease. Under the Fxy, max condition, the yield strength is exceeded, which affects the safety of the wind power tower. This research will provide a theoretical reference for the safety determination of actual wind power towers with welding defects.

Keywords

• wind turbine tower
• ring weld
• porosity defect
• cracking
• sub-model