Thermographic inspection of wind turbine rotor blade segment utilizing natural conditions as excitation source, Part II: The effect of climatic conditions on thermographic inspections – A long term outdoor experiment

Worzewski, Tamara; Krankenhagen, Rainer; Doroshtnasir, Manoucher

doi:10.1016/j.infrared.2016.04.012

Cited by 18 publications

(8 citation statements)

References 5 publications

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“…7) which was constructed according to Section 3.2. Please note that the crack at the leading edge can be observed in a thermogram when the IR-camera position is not exactly perpendicular to ROBAS surface as will be presented in part II [32] in other thermograms which include ROBAS' leading edge. In the calculated FEM model of Fig.…”

Section: Experimental and Modelled Results Of Robasmentioning

confidence: 99%

“…Please note that the temperature range was dynamically adapted for achieving best possible visualization of thermal contrasts on the pressure side's surface. thermography during different times of day, seasons and weather conditions to evaluate favorable conditions for monitoring, which is subject of the next part II [32].…”

Section: Discussionmentioning

confidence: 99%

“…In this study (part I), the potential of thermography to detect subsurface structures in GFRP is evaluated, when the sun is utilized as the main excitation source (a scenario which will be referred to as ''solar thermography" in the following). Other natural environmental conditions and climatic effects on thermographic measurements will be discussed in a separate publication (part II [32]). …”

Section: Introductionmentioning

confidence: 99%

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Thermographic inspection of a wind turbine rotor blade segment utilizing natural conditions as excitation source, Part I: Solar excitation for detecting deep structures in GFRP

Worzewski

Krankenhagen

Doroshtnasir

et al. 2016

Infrared Physics & Technology

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Section: Experimental and Modelled Results Of Robasmentioning

confidence: 99%

Section: Discussionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Thermographic inspection of a wind turbine rotor blade segment utilizing natural conditions as excitation source, Part I: Solar excitation for detecting deep structures in GFRP

Worzewski

Krankenhagen

Doroshtnasir

et al. 2016

Infrared Physics & Technology

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“…Early morning experiments provided a visible contrast of the defects on the defect plate attached to the damaged blade section primarily due to the considerable temperature change on the blade during this period [2,18,19]. All defects in the plate, except the smallest 4 mm ones, were detected during this period.…”

Section: Passive Thermographymentioning

confidence: 99%

“…They mounted an IR camera on an unmanned aerial vehicle (UAV) and captured thermal images of installed blades while the blades were stationary, demonstrating the capability for fast data acquisition and inspection with this setup. Other research evaluated the suitability of different weather conditions for revealing the internal features of a blade section with thermal imaging [18,19]. Doroshtnasir [20] proposed a new passive thermography technique that can inspect operating blades from the ground.…”

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confidence: 99%

Condition Monitoring of Wind Turbine Blades Using Active and Passive Thermography

2018

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The failure of wind turbine blades is a major concern in the wind power industry due to the resulting high cost. It is, therefore, crucial to develop methods to monitor the integrity of wind turbine blades. Different methods are available to detect subsurface damage but most require close proximity between the sensor and the blade. Thermography, as a non-contact method, may avoid this problem. Both passive and active pulsed and step heating and cooling thermography techniques were investigated for different purposes. A section of a severely damaged blade and a small "plate" cut from the undamaged laminate section of the blade with holes of varying diameter and depth drilled from the rear to provide "known" defects were monitored. The raw thermal images captured by both active and passive thermography demonstrated that image processing was required to improve the quality of the thermal data. Different image processing algorithms were used to increase the thermal contrasts of subsurface defects in thermal images obtained by active thermography. A method called "Step Phase and Amplitude Thermography", which applies a transform-based algorithm to step heating and cooling data was used. This method was also applied, for the first time, to the passive thermography results. The outcomes of the image processing on both active and passive thermography indicated that the techniques employed could considerably increase the quality of the images and the visibility of internal defects. The signal-to-noise ratio of raw and processed images was calculated to quantitatively show that image processing methods considerably improve the ratios. the blade [10]. Since access to a blade is difficult and requires an industrial climber or crane, which can be dangerous and/or time-consuming, the practical implementation of conventional methods sometimes requires blade removal. Developing new NDT techniques that are capable of detecting faults in the blades from larger distances is essential.Infrared (IR) thermography is a non-contact, long-distance NDT technique that can inspect extensive areas quickly by capturing thermal images of the object's surface. In general, defective areas alter the temperature distributions on the surface that are measured by IR cameras. Thermographic inspection is typically divided into two categories: active and passive. In active thermography, different heating sources such as flash and halogen lamps are employed for heating the object making the technique less usual for operating wind turbines. It is used here largely to allow comparison with passive thermography which utilizes solar radiation [2] to heat a blade (usually around sunrise) or to cool it at sunset. This method has been widely used to detect subsurface defects of different materials including metals [11], composites [12,13], and concrete [14].Different studies have used thermography to detect faults in wind turbine blades. Meinlischmidt and Aderhold [2] employed passive thermography to detect internal structural features and subsurface defects s...

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AQUADA: Automated quantification of damages in composite wind turbine blades for LCOE reduction

et al. 2020

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Reliability and cost are two important driving factors in the development of wind energy. Automation and digitalization of operation and maintenance (O&M) procedures help to increase turbine reliability and reduce the levelized cost of energy (LCOE). Here, we demonstrate a novel method, coined as AQUADA, which may change the current labor‐intensive and operation‐interfering blade inspection by using thermography and computer vision. We experimentally show that structural damages below the surfaces can be detected and quantified remotely when wind turbine blades are subject to fatigue loads. The data acquisition and analysis are automatically done in one single step, which may shift the current inspection paradigm through more automated O&M procedures. The cost analysis shows that the AQUADA method has a potential to at least half the total inspection cost and reduce the LCOE by 1%–2% when applied to a baseline land‐based wind farm consisting of twenty 2.45‐MW turbines. All data and source codes are published for researchers to reproduce our results and facilitate further development of AQUADA towards more mature industrial applications.

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Thermographic inspection of wind turbine rotor blade segment utilizing natural conditions as excitation source, Part II: The effect of climatic conditions on thermographic inspections – A long term outdoor experiment

Cited by 18 publications

References 5 publications

Thermographic inspection of a wind turbine rotor blade segment utilizing natural conditions as excitation source, Part I: Solar excitation for detecting deep structures in GFRP

Thermographic inspection of a wind turbine rotor blade segment utilizing natural conditions as excitation source, Part I: Solar excitation for detecting deep structures in GFRP

Condition Monitoring of Wind Turbine Blades Using Active and Passive Thermography

AQUADA: Automated quantification of damages in composite wind turbine blades for LCOE reduction

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