Abstract
Thickness transitions in load carrying elements lead to improved geometries and efficient material utilization. However, these transitions may introduce localized areas with high stress concentrations and may act as crack initiators that could potentially cause delamination and further catastrophic failure of an entire blade structure. The local strength degradation under an ultimate static loading, subsequent to several years of fatigue, is predicted for an offshore wind turbine blade. Fatigue failure indexes of different damage modes are calculated using a sub-modeling approach. Multi axial stresses are accounted for using a developed failure criterion with residual strengths instead of the virgin strengths. Damage initiation is predicted by including available Wohler curve data of E-Glass fabrics and epoxy matrix into multi-axial fatigue failure criteria. As a result of this study, proper knock-down factors for ply-drop effects in wind turbine blades under multi-axial static and fatigue loadings can be obtained.
| Original language | English |
|---|---|
| Title of host publication | 37th Risø International Symposium on Materials Science |
| Editors | B. Madsen, A. Biel, Y. Kusano, H. Lilholt, L.P. Mikkelsen, L. Mishnaevsky Jr., B.F. Sørensen |
| Number of pages | 8 |
| Publisher | IOP Publishing |
| Publication date | 2 Sept 2016 |
| Pages | 237-244 |
| Article number | 012022 |
| ISBN (Print) | 978-87-93278-94-3 |
| DOIs | |
| Publication status | Published - 2 Sept 2016 |
| Event | 37th Risø International Symposium on Materials Science 5–8 September 2016, Risø, Denmark - Department of Wind Energy Technical University of Denmark Risø Campus , Roskilde, Denmark Duration: 5 Sept 2016 → 9 Sept 2016 http://www.vindenergi.dtu.dk/english/Research/Conferences/Symp37 |
Conference
| Conference | 37th Risø International Symposium on Materials Science 5–8 September 2016, Risø, Denmark |
|---|---|
| Location | Department of Wind Energy Technical University of Denmark Risø Campus |
| Country/Territory | Denmark |
| City | Roskilde |
| Period | 05/09/2016 → 09/09/2016 |
| Internet address |
| Series | IOP Conference Series: Materials Science and Engineering |
|---|---|
| Number | 1 |
| Volume | 139 |
| ISSN | 1757-8981 |
Bibliographical note
@article{1757-899X-139-1-012022,author={Seyed Aydin Raeis Hosseiny and Johnny Jakobsen},
title={Local fatigue behavior in tapered areas of large offshore wind turbine blades},
journal={IOP Conference Series: Materials Science and Engineering},
volume={139},
number={1},
pages={012022},
url={http://stacks.iop.org/1757-899X/139/i=1/a=012022},
year={2016},
abstract={Thickness transitions in load carrying elements lead to improved geometries and efficient material utilization. However, these transitions may introduce localized areas with high stress concentrations and may act as crack initiators that could potentially cause delamination and further catastrophic failure of an entire blade structure. The local strength degradation under an ultimate static loading, subsequent to several years of fatigue, is predicted for an offshore wind turbine blade. Fatigue failure indexes of different damage modes are calculated using a sub-modeling approach. Multi axial stresses are accounted for using a developed failure criterion with residual strengths instead of the virgin strengths. Damage initiation is predicted by including available Wohler curve data of E-Glass fabrics and epoxy matrix into multi-axial fatigue failure criteria. As a result of this study, proper knock-down factors for ply-drop effects in wind turbine blades under multi-axial static and fatigue loadings can be obtained.}
}
Keywords
- Fatigue analysis
- Damage Criteria
- Failure Mode Analysis
- Wind turbine blades : Composite materials : Delamination buckling : Adhesive failure :Fracture mechanics