Fatigue Failure of a Composite Wind Turbine Blade at the Trailing Edge

Abstract:

The downtime problem of wind turbine increases due to fatigue damage of wind turbine blades, which is even more crucial in the larger blades. One of the critical failure modes is the blade trailing edge failure, which can result in the trailing edge joint cracked. In this paper, we experienced that abnormal sound was happened in the trailing edge at the cross-section in the max chord during fatigue testing of a 2 MW full-scale wind turbine blade according to IEC61400-23. Through the conditional monitoring of the trailing edge, the delamination between GFRP and balsa wood is caused by stress concentration. The abnormal sound is happened due to GFRP beat the balsa wood when the blade vibrates in the edgewise direction. Moreover, the sound is amplified because the introduction of air due to the delamination. The local stress distribution and stability factors are computed through FEM methods, the program that increasing the core materials in the trailing edge is proposed. Therefore the structure reliability in the trailing edge is improved.

• Periodical: Defect and Diffusion Forum (Volume 382)
• Pages: 191-195
• DOI: https://doi.org/10.4028/www.scientific.net/DDF.382.191
• Online since: January 2018
• Authors: Zu Jin Pan*, Jian Zhong Wu, Jian Liu, Xin Hua Zhao
• Keywords: Abnormal Sound, Composite, Delamination, Fatigue Failure, Wind Turbine Blade

References

[1] S. Sheng, Report on wind turbine subsystem reliability-A survey of various databases, technical report, NREL/PR-5000-59111, accessed: 2015-04- 24.

[2] S. Yang,Y. Huang, X. Zhong, et al. Analysis of static loading test failure for a large wind turbine blade[J]. Dongfang Turbine, 2015, 2: 25-29.

[3] F.M. Jensen B.G. Falzon, J. Ankersen, et al. Structural testing and numerical simulation of a 34m composite wind turbine blade[J]. Composite Structures, 2006, 76: 52-61.

DOI: 10.1016/j.compstruct.2006.06.008

[4] Hakgu Lee, Min Gyu Kang, Jisang Park. Fatigue failure of a composite wind turbine blade at its root end[J]. Composite Structures, 2015, 133: 878–885.

DOI: 10.1016/j.compstruct.2015.08.010

[5] Hakgu Lee, Jisang Park. Static test until structural collapse after fatigue testing of a full-scale wind turbine blade [J]. Composite Structures, 2016, 136: 251–257.

DOI: 10.1016/j.compstruct.2015.10.007

[6] J Yang, C Peng, J Xiao, J Zeng, S Xing, J Jin, et al. Structural investigation of composite wind turbine blade considering structural collapse in full-scale static tests. Compos Structures, 2013, 97: 15–29.

DOI: 10.1016/j.compstruct.2012.10.055

[7] M. A. Eder. A practical approach to fracture analysis at the trailing edge of wind turbine rotor blades [J]. Wind Energy, 2014, 17: 483-497.

DOI: 10.1002/we.1591

[8] IEC 61400-23: International Standard IEC 61400-23 Wind Turbines–Part 23: Full-Scale Structural Testing of Rotor Blades, IEC: Geneva, Switzerland, (2014).

DOI: 10.1109/iclp.2018.8503411