A year-long monitoring of preloaded free-maintenance bolts – Estimation of preload loss on BobTail bolts

Real-time monitoring, prognosis, and resilient control for wind turbine systems

“…For the knowledge-based method, the implicit relationship among the wind turbine system variables, referred to as the knowledge base, is extracted from the historical data via training or statistical analysis, and monitoring/fault diagnosis is implemented by checking the consistency between the knowledge base and the real-time wind turbine relationship extracted by using online data analysis and processing. In this special issue, there are 11 papers selected, with a focus on monitoring and fault diagnosis, which uses signal-based [4][5][6][7][8], knowledge-based methods [9][10][11][12][13] and mode-based methods [14], respectively.…”

“…To increase the height of towers for exploiting stronger and more stable wind profiles, a welded-free friction connection seems to be promising for the new generation of wind towers, which requires a reliable monitoring and estimation on the performance of bolts over time. In the paper [12] contributed by Matos et al, a monitoring and identification procedure is presented for a 1-year monitoring of the force and temperature in a prototype. By using data-driven nonlinear identification, a nonlinear Hammerstein-Wiener model is built, which is used to estimate the preload losses of the bolts for 20 years of the tower lifetime.…”

Resonance of steel wind turbines: Problems and solutions

“…Moreover, additional to the well-known onshore and offshore wind parks, small scale horizontal and vertical wind turbines are now also being installed in private properties [5]. The onshore steel turbines are generally realized using a tubular steel column with different diameters along with the height while the offshore structures are a mix solution between lattice trussed and tubular columns [6,7].…”

Health assessment of a multi-bolted connection due to removing selected bolts

“…However, the most common method of measuring bolt forces is the method based on the use of resistance strain gauges. The measurements are made by means of strain gauges glued to the outside of the bolt shank [41]- [46], inserted into the hole inside the bolt shank [47][48][49][50][51] or on the bolt head [52]. In addition to ultrasonic sensing, it is the method with the highest accuracy [36].…”