An experimental study of acoustic emission methodology for in service condition monitoring of wind turbine blades

Wind turbine blade certification tests, comprising a static test, a fatigue test, and finally a residual strength test, often involve sudden audible cracking sounds from somewhere within the blade, without the operators being able to locate the noise source, or to determine whether damage (minor or major) has occurred. A current EC-funded research project is looking at the possibility of using acoustic emission (AE) monitoring during testing of fibre composite blades to detect such events and assess the blade condition. AE can both locate and characterise damage processes in blades, starting with non-audible signals occurring due to damage propagation at relatively low loads. The test methodology is discussed in the context of the blade certification procedure and results are presented from a series of static and fatigue blade tests to failure in the laboratory. Inferences are drawn about small differences in the manufacture of the nominally identical blades and conclusions are presented for the application of the methodology.

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Evaluation of Fatigue Damage for Wind Turbine Blades Using Acoustic Emission

Journal of the Korean Society for Nondestructive Testing ◽

10.7779/jksnt.2015.35.3.179 ◽

2015 ◽

Vol 35 (3) ◽

pp. 179-184

Author(s):

Hyun-Sup Jee ◽

No-Hoe Ju ◽

Cheal Ho So ◽

Jong-Kyu Lee

Keyword(s):

Acoustic Emission ◽

Wind Turbine ◽

Fatigue Damage ◽

Turbine Blades ◽

Wind Turbine Blades

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Experimental study of particle dampers applied to wind turbine blades to reduce low-frequency sound emission

INTER-NOISE and NOISE-CON Congress and Conference Proceedings ◽

10.3397/in-2021-1125 ◽

2021 ◽

Vol 263 (6) ◽

pp. 71-82

Author(s):

Braj Bhushan Prasad ◽

Fabian Duvigneau ◽

Daniel Juhre ◽

Elmar Woschke

Keyword(s):

Experimental Study ◽

Granular Material ◽

Wind Turbine ◽

Laser Scanning ◽

Turbine Blades ◽

Low Frequency ◽

Small Scale ◽

Full Potential ◽

Sound Emission ◽

Wind Turbine Blades

Sound emission from an onshore wind turbine is one of the significant hurdles to use wind energy to its full potential. The vibration caused by the generator is transmitted to the blades, which radiates the sound to the surrounding. The purpose of this experimental study is to present a passive vibration reduction concept, which is based on the high damping properties of granular materials. The efficiency of this concept will be investigated using a laser scanning vibrometer device. For the experimental purpose in the laboratory, small-scale replicas inspired by the original configurations are used as reference geometries for the wind turbine generator and the blades. Vibrations of the prototype, with and without granular material filling, will be determined and compared with each other. The influence of the amount of granular material inside the structure is also investigated. Apart from this, different types of granular filling are examined with respect to their efficiency in reducing the amplitude of vibration of the structure while being as light as possible in order to design a lightweight solution, which increases the overall mass of the wind turbine marginally.

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