INVESTIGATING FATIGUE LIFE IN BOLTED FLANGE CONNECTION IN WIND TURBINE TOWERS

Abstract

A comprehensive assessment of fatigue was performed on an L-flanged bolted connection under four different wind speeds. The wind turbines were subjected to average wind speeds of 5, 10, 15, and 20 m/s. The primary objective was to investigate how the fatigue life was influenced by increasing the number and size of bolts while also developing a systematic approach for analyzing the fatigue life of bolted flange connections more broadly. The study determined that increasing the size or number of bolts can notably improve the fatigue life of bolted flange connections. Additionally, the curves derived from the assessment data demonstrated a steeper slope for a greater number of bolts, indicating that the percentage increase of adding bolts is not consistent for each additional bolt. Instead, the percentage increment rises exponentially when increasing the number of bolts. However, selecting the most suitable design improvement strategy depends on the specific circumstances. For example, increasing the number of bolts may not always be possible due to spatial limitations. In the majority of cases, the study observed that increasing the number of bolts resulted in significant improvements in fatigue life, regardless of the size of the bolts used. This noteworthy finding can be particularly advantageous when assessing the cost-effectiveness of possible solutions for enhancing the durability of bolted flange connections.