Project Details
Description
The WindWeld project is investigating how to improve the fatigue life of circumferential welds of the steel structures of offshore wind turbine farms (ex. towers and monopiles). The main method for improving the life of the welds is to mill away the weld toe and the development of a milling robot capable of processing circumferential welds is done by the partner MAXARS. A large fatigue testing program of industrial scale weld samples in the form of dog-bone specimens with dimensions 600 mm x 120 mm x 25 mm is conducted in order to obtain S-N curves documenting the fatigue properties of the treated welds.
Siemens Gamesa Renewable Energy is the principle investigator of the EUDP funded project. Their main focus is on the manufacturing of the industrial size test specimens and on obtaining S-N curves of tower relevant welds treated with the milling robot. The partners Ørsted, Vattenfall, Cowi and Rambøll are also focused on the effect of pre-corrosion on the fatigue life of welds treated by either milling or by the standard method of ground flushing. The current procedure of painting the treated welds before shipping the steel structures to the storage facilities might be omitted, if it can be proven that 1 year of pre-corrosion at either the storage quay site or if installed in the sea but without a functioning corrosion protection system does not have a significant impact of the fatigue life of the welds. A dedicated work package is focused on pre-corroding the large scale dog bone samples in salt spray chambers and to establish the effect on the remaining fatigue life of the welds. The fatigue testing and some of the salt chamber sample treatment is performed by external partners Force Technology and Danish Technological Institute. Finally DVNGL is used as external consultant to ensure that obtained S-N curves are likely to be used in future designs of offshore wind farms.
The role of DTU Wind Energy is organized in a supporting research work package to the industrial tests. The tasks of DTU is focused the following tasks:
1) An analysis of the buckling limit of 10 MW offshore wind turbine towers if the tower wall thickness is reduced according to the improved fatigue life by introducing the circumferential weld milling robot. An economical impact evaluation of the reduced tower wall thickness will be performed. Contact: Martin Eder and Asger B. Abrahamsen
2) 3D X-ray tomography analysis of the surface roughness of the steel below the corrosion layer of industrial relevant samples pre-corroded in salt spray chambers and relating this to pre-corrosion obtained in realistic offshore environment at the Fraunhofer corrosion test site Helgoland located in the North Sea. DTU has facilitated the installation of 40 industrial scale dogbones at Helgo for subsequent fatigue testing. Tomography Corrosion Coupons has been installed along with industrial dog bones to investigate the corrosion state. Contact: Søren Fæster and Asger B. Abrahamsen
3) Investigation if pitting of the steel surface obtained from 3D x-ray tomography can be observed and an investigation of the impact of the pitting on the fatigue life of the resulting steel samples. Lab scale dog-bone samples have been manufactured from the left overs from the industrial samples and the a prediction of the fatigue failure region of such pre-corroded samples will be attempted based on the 3D x-ray tomography scans of the samples before fatigue testing. Contact: Ali Sarhadi and Asger B. Abrahamsen
It is believed that X-ray tomography can be used to quantify the corrosion state of steel structures at offshore wind farms in the future and it opens up for the possibility to accelerated pre-corrosion in salt spray chambers if the relation to real offshore environment can be justified.
Siemens Gamesa Renewable Energy is the principle investigator of the EUDP funded project. Their main focus is on the manufacturing of the industrial size test specimens and on obtaining S-N curves of tower relevant welds treated with the milling robot. The partners Ørsted, Vattenfall, Cowi and Rambøll are also focused on the effect of pre-corrosion on the fatigue life of welds treated by either milling or by the standard method of ground flushing. The current procedure of painting the treated welds before shipping the steel structures to the storage facilities might be omitted, if it can be proven that 1 year of pre-corrosion at either the storage quay site or if installed in the sea but without a functioning corrosion protection system does not have a significant impact of the fatigue life of the welds. A dedicated work package is focused on pre-corroding the large scale dog bone samples in salt spray chambers and to establish the effect on the remaining fatigue life of the welds. The fatigue testing and some of the salt chamber sample treatment is performed by external partners Force Technology and Danish Technological Institute. Finally DVNGL is used as external consultant to ensure that obtained S-N curves are likely to be used in future designs of offshore wind farms.
The role of DTU Wind Energy is organized in a supporting research work package to the industrial tests. The tasks of DTU is focused the following tasks:
1) An analysis of the buckling limit of 10 MW offshore wind turbine towers if the tower wall thickness is reduced according to the improved fatigue life by introducing the circumferential weld milling robot. An economical impact evaluation of the reduced tower wall thickness will be performed. Contact: Martin Eder and Asger B. Abrahamsen
2) 3D X-ray tomography analysis of the surface roughness of the steel below the corrosion layer of industrial relevant samples pre-corroded in salt spray chambers and relating this to pre-corrosion obtained in realistic offshore environment at the Fraunhofer corrosion test site Helgoland located in the North Sea. DTU has facilitated the installation of 40 industrial scale dogbones at Helgo for subsequent fatigue testing. Tomography Corrosion Coupons has been installed along with industrial dog bones to investigate the corrosion state. Contact: Søren Fæster and Asger B. Abrahamsen
3) Investigation if pitting of the steel surface obtained from 3D x-ray tomography can be observed and an investigation of the impact of the pitting on the fatigue life of the resulting steel samples. Lab scale dog-bone samples have been manufactured from the left overs from the industrial samples and the a prediction of the fatigue failure region of such pre-corroded samples will be attempted based on the 3D x-ray tomography scans of the samples before fatigue testing. Contact: Ali Sarhadi and Asger B. Abrahamsen
It is believed that X-ray tomography can be used to quantify the corrosion state of steel structures at offshore wind farms in the future and it opens up for the possibility to accelerated pre-corrosion in salt spray chambers if the relation to real offshore environment can be justified.
Key findings
Introduction of a robot capable of milling circumferential welds of offshore wind turbine towers and monopiles in order to improve the fatigue life time.
Establishing fatigue life S-N curves of industrial relevant size samples holding welds treated by robot milling or ground flushing.
Pre-corrosion of industrial samples in real offshore environment at the Fraunhofer corrosion test site Helgoland in the north sea and fatigue life investigation.
Establishing fatigue life S-N curves of industrial relevant size samples holding welds treated by robot milling or ground flushing.
Pre-corrosion of industrial samples in real offshore environment at the Fraunhofer corrosion test site Helgoland in the north sea and fatigue life investigation.
| Short title | WindWeld - WP5 |
|---|---|
| Acronym | WindWeld - WP5 |
| Status | Finished |
| Effective start/end date | 25/02/2019 → 31/12/2021 |
Collaborative partners
- Technical University of Denmark
- COWI A/S (Joint applicant)
- Ramboll Foundation (Joint applicant)
- Maxars A/S (Joint applicant)
- FORCE Technology (Project partner)
- Danish Technological Institute (Project partner)
- Siemens Gamesa Renewable Energy A/S (Joint applicant) (lead)
- Ørsted A/S (Joint applicant)
- Vattenfall Vindkraft A/S (Joint applicant)
Keywords
- Offshore wind turbine
- Weld
- Fatigue life
- Corrosion
Fingerprint
Explore the research topics touched on by this project. These labels are generated based on the underlying awards/grants. Together they form a unique fingerprint.