Wölfel Wind Systems – Structural Health Monitoring, Ice Detection, Dampers for Tonalities and Vibrations

Strong vibrations accelerate material fatigue and the risk of damage, such as cracks in the rotor blades, may increase significantly. When wind turbines start to vibrate, individual frequencies in the background noise of the turbine can also become audible – this is referred to as tonality. As these are perceived as particularly unpleasant for humans, they usually lead to a more negative evaluation of the sound emission, often leading to the systems only being allowed to run in sound-reduced mode.

Vibrations can therefore cause additional costs in several ways and lead to yield losses. As a rule, they cannot be completely avoided, but they can be significantly reduced. There are various methods of reducing vibrations, including the use of passive and active absorbers. As experts in vibrations and acoustics, we have extensive experience in this field and have specialized in solving vibration problems with our sound knowledge of structural mechanics and dynamics.

Reducing vibrations and thus avoiding extreme loads is essential, especially with regard to a possible continued operation after the design lifetime has expired. By using Structural Health Monitoring (SHM) systems, the remaining service life can be calculated on the basis of the fatigue loads that have actually occurred, the design model can be optimized and thus a well-founded decision can be made about the continued operation.

Only if the individual components of the wind turbine as well as the loads and stresses are precisely known can you react quickly to deviations and damage and initiate effective countermeasures. Structural Health Monitoring (SHM) systems therefore collect large amounts of data, in particular structural-mechanical parameters such as acceleration, displacement and stretch. The decisive task, however, is the evaluation and interpretation of this measured data.

We have been developing intelligent algorithms for signal analysis for more than 40 years and integrate additional operating and environmental conditions in the evaluation. This is what we call Structural Intelligence. The result is detailed knowledge of the state of the structure. On this basis, diagnoses can be made, risks calculated, forecasts made and clear recommendations for action derived.

However, we do not only offer tools for analysis. From the planning and conception of an SHM system to the installation and commissioning through to the preparation and visualization of the collected data, you receive all services from a single source.

Higher and more constant wind speeds than on land make the sea an attractive location for wind farms. At the same time, the wind turbines there are also exposed to extreme environmental influences. Strong waves and high wind speeds lead to high dynamic loads. This results in increased requirements during both installation and operation.

The investment costs for offshore wind turbines are generally higher than for turbines on land. With a view to rapid amortization, efficient and trouble-free operation is essential.  Structural Health Monitoring (SHM) allows for damage to be detected at an early stage thus minimizing downtimes tor even completely avoiding them. 

SHM can also reduce the number of usually expensive, risky and weather-dependent visual inspections (periodic inspections) to the minimum recommended by the Federal Maritime and Hydrographic Agency (BSH). Ideally, inspections are not carried out periodically, but on a risk basis. Errors with a high risk of failure or damage are identified and prioritized, and targeted inspections can be planned with foresight.