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Reaction Washers to Improve Work Safety and Preload Accuracy with Powered Torque Tools
Bolted joints in wind turbines are subjected to extreme loads due to high forces in axial and transversal directions, for example in rotor blades, turbines and flange connections in the towers. Because the loads are dynamic, the bolted joints are endangered by fatigue failure and self-loosening throughout their entire service life. Consequently, correct bolt dimensioning analysis results in bolted joints with high preloads and large diameters. But even if the preload is accurately calculated it must be reliably and safely applied during assembly using high tightening torques. High preload bolts with diameters of M24 and larger can no longer be tightened manually with a handheld torque wrench. Instead, they require powered torque tools (hydraulic, electric or battery-operated) along with reaction arm support structures to manage the high reaction forces. Finally, the required preload must be maintained during operation where alternating loads, especially in the transversal direction caused by wind loads, vibrations from the rotor, etc., can lead to self-loosening.
By Tobias Hübing, Head of Laboratory, Heico Group, Germany
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Virtual Sensors Extend Structural Health Monitoring Across the Entire Wind Farm
Asset integrity management encompasses comprehensive approaches to ensuring the structural integrity, reliability and longevity of offshore wind turbines and foundations. This framework integrates monitoring, inspection, maintenance and risk management strategies. In the bottom-fixed wind sector, current best practices typically involve deploying structural health monitoring (SHM) systems on only a fraction of turbines within a farm (typically 10%), while the others receive minimal or no instrumentation. SHM systems use sensors such as strain gauges and accelerometers, with data analysed either continuously or periodically to evaluate the condition of structural components. However, this approach faces two key challenges: 1) the substantial initial and operational costs of implementing and maintaining SHM systems and 2) the limited sensor coverage, both in terms of the number of turbines monitored across a farm and the number of measurement points per turbine.
By Ambroise Cadoret, Fabien Caleyron and Vincent Le Corre, GreenWITS, France
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Handling and Storage: Damage Risks and Mitigation Measures
The journey that a wind turbine blade takes from the factory to the turbine carries a risk of structural damage to the blade. From its work with multiple industry stakeholders, DNV has observed and investigated damage to, and the failure of, blades during the journey. Even relatively minor damage from transportation, handling or storage can worsen during operation. Such damage may result in the need for repair or, in severe cases, blade failure. Damage observed by DNV from transportation, handling and storage has ranged in severity from scratches to the blade coating where support fixtures made contact with the blade to damage to primary structural members of the blade, requiring replacement of the blade. Understanding these risks and how to mitigate them is important for protecting project investments and maximising blade durability.
By Matthew Malkin, Principal Engineer, DNV, USA
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Challenges in Blade Bearing Operation
In recent years, the wind energy industry has faced a growing number of challenges related to the condition and durability of blade bearings. These critical components, which connect the rotor blades to the hub of a wind turbine, are exposed to highly dynamic loads during operation. Increasingly, operators and service providers have observed cracks, raceway damage and premature wear across various manufacturers and turbine models, including power classes between 2 and 8MW onshore and offshore. As turbines become older and are subjected to higher operational stresses, the mechanical loads acting on the blade bearings become more complex and variable. This accelerates fatigue processes and increases the risk of unexpected bearing failures.
By Moritz Hemmerlein and Hélène Guillerm, eolotec, Germany
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Timber Hybrid Towers for Wind Turbines
The demand for taller towers for wind turbines has been growing steadily for years. As tower heights increase so do the requirements for structural design and material efficiency. Conventional tower construction methods are increasingly reaching their technical and economic limits. Could timber hybrid towers be a suitable alternative to meet the increasing static requirements while enabling more efficient use of materials?
By Werner Mussnig and Roman Braun, Hasslacher Green Tower, Austria
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Moving Beyond Prediction with AI-Based Detection Models
The wind industry faces immense pressure to maximise asset availability and reduce operational expenditure. Traditional maintenance strategies, whether based on fixed schedules or simple alerts, often fall short, leading to costly unplanned downtime, unnecessary component replacements, and missed opportunities for optimisation. The challenge is moving from predictive models, which only forecast a failure, to prescriptive maintenance, which provides specific, actionable recommendations. This article provides a technical explanation of how artificial-intelligence-based detection models bridge this gap, using complex data to diagnose developing faults and prescribe a clear course of action, ultimately improving turbine reliability and reducing O&M costs.
By Silvio Rodrigues, Chief Innovation Officer and Co-founder, Jungle, Portugal
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ZX 300e Wind Lidar Achieves IEC 21- to 200-Metre Classification
The global wind industry continues its advances towards ever-larger turbines. Whereas hub heights of 80 to 100 metres were once considered tall, today’s turbines are routinely installed at hub heights exceeding 120 to 160 metres, with rotor diameters of 170 to 200 metres. This scale of technology demands a measurement solution that can provide finance-grade wind data across the full rotor swept area. Without such measurement certainty, wind projects risk underperformance, increased cost of capital, and reduced investor confidence.
By Alex Woodward and James G. Downs, ZX Lidars, UK
