<p>Wind turbine tower flange connections rely on hundreds of high-strength bolts, and the dispersion of preload directly determines the sealing performance and fatigue life of the flange surface. Engineering practice shows that fretting wear caused by insufficient preload is the primary cause of early bolt failure in tower structures.</p>
<p>During the construction phase, it is recommended to use the hydraulic tensioning method, combined with angle measurement for verification, which can keep the preload dispersion within ±5%.</p>
<p>There are three key points during the operation and maintenance phase. First, a comprehensive re-inspection should be conducted in the first year after commissioning, focusing on loose bolts and cracks. Second, subsequent inspections should be carried out every five years, with a sampling rate of no less than 10%. Third, when replacing bolts, all must be of the same specification; mixing different batches or manufacturers is strictly prohibited.</p>
<p>Digital technologies are becoming increasingly widespread. Smart washers equipped with built-in sensors can transmit real-time preload data, upgrading passive inspections to predictive maintenance, and have already been deployed in multiple newly constructed wind farms.</p>