Environmental Engineering Reference
In-Depth Information
condition to further verify the proposed method in this work. The experi-
mental results obtained were similar w.r.t. modal parameters. An analysis
shows that the proposed method is able to largely remove the effects of
rotation.
(2) Fatigue damage detection system using a high spatial resolution DPP-BOT-
DA is successfully developed and experimentally validated. Polarization-
maintaining optical fibers were bonded on the surface of wind turbine blade
to form the distributed sensing network. The strain distributions obtained by
the DPP-BOTDA system at different fatigue cycle count validated the
effectiveness of the developed system in damage detection and distributed
sensing. The shape of the BGS was sensitive to fatigue damage as the stiff-
ness degradation and accumulated cracks change local strain gradient which
can be used to locate the serious fatigue damage. The developed system
shows its potentiality for developing highly reliable wind turbine monitoring
system.
(3) An experiment is designed to study the damage detection techniques based on
optical fiber sensors, PZT sensors, and the fractal dimension-based damage
detection method. From the direct results of optical fiber sensors, it can
observe the strain increase and also determine the strain distribution through
the blade surface. This information is important to study concerned topic on
the static and dynamic properties of this composite blade, for example, the
fatigue characteristic, etc. From the results of PZT sensors, in the later part of
the test when the cracks produce, it can obviously detect the signal from
cracks. Then, the fractal dimension-based damage detection method was
employed to calculate the damage index and results are encouraged.
It should be pointed out that the most important and difficult problems for
structural health monitoring and damage detection are the actual application of the
above techniques. Such as the data measured under changing environmental and
operational conditions will be effected by noise and so on, the application also
requires the fast decision based on the damage detection algorithms. These
approaches should be further developed for online monitoring of wind blades.
References
1. Schroeder K, Ecke W, Apitz J et al (2006) A Fibre Bragg Grating sensor system monitors
operational load in a wind turbine rotor blade. Meas Sci Technol 17(5):1167-1172
2. Krämer SGM, Wiesent B, Müller MS et al (2008) Fusion of a FBG-based health monitoring
system for wind turbines with a Fiber-optic lightning detection system. In: Proceeding of
SPIE 7004, 19th international conference on optical fibre sensors, 70040O; doi:
10.1117/12.
3. Ecke W, Schröder K (2008) Fiber Bragg Grating sensor system for operational load
monitoring of wind turbine blades. In: Proceeding of SPIE 6933, Smart Sensor Phenomena,
Technology, Networks and Systems, 69330I; doi:
10.1117/12.783602
