Failure investigation on a coastal wind farm damaged by super typhoon: A forensic engineering study

Abstract

This study presented a failure investigation on a wind farm which is located on the southeast coast of Mainland China and was severely damaged by two super typhoons: i.e., Dujuan in 2003 and Usagi in 2013. Failure characteristics of the wind farm in terms of rotor blade damage, tubular tower collapse and wind turbine (WT) burn were examined from a forensic engineering perspective. A systematic procedure was proposed to quantitatively investigate structural failure by calculating the extreme wind loads and re-constructing structural models for composite blades and steel towers. It was found that both extreme winds and the stop positions of WTs were critical to turbine failure due to the change of wind direction during typhoon impact. The overstrain/overstress was identified as the plausible root cause for structural failure of WTs. In addition, the dramatic reduction of shell wall thickness due to possible design defect was also found to be responsible for the tower collapse in this study.