ANALYTICAL FATIGUE DAMAGE CALCULATION FOR WIND TURBINE SUPPORT STRUCTURE

Fatigue plays an important, often crucial role in the design of wind turbine support structures due to the large number of wind-induced and operational stress cycles. Flexibility of the tower foundation is usually specified during the turbine design certification to achieve a natural frequency to reduce dynamic resonance with the turbine operational frequencies which could significantly increase the fatigue damage and possibly reduce operational design life. This research presents a practical analytical procedure of quantifying fatigue damage, investigates the impact of different foundation flexibility on fatigue life, and compares the results with measured response of the Case Western Reserve University campus turbine. A turbulent wind history is simulated, resulting tower and blade loads calculated, and applied to a finite element model of the wind turbine. The wind loads were applied to the analytical model to calculate the dynamic response of a parked turbine. A fatigue damage metric based on the tower base overturning moment response was defined and calculated for the ten minute simulation and compared with actual measured response under similar conditions (i.e. average wind speed, parked turbine). Fatigue damage is quantified using a rainflow cycle counting method. By comparing the numerical simulation with the real recorded data, the analytical method proved to be reliable. For the cases considered, it was also observed that the fatigue damage of flexible-base foundations was reduced compared to that of fixed-base foundation.

Name thesis:degree_name

Master of Sciences

Level thesis:degree_level

masters

Discipline thesis:degree_discipline

Civil Engineering

Grantor dc:publisher

Case Western Reserve University School of Graduate Studies

Year dc:date

2013

Author dc:creator

• Li, Jiale

Contributors dc:contributor

• Pollino, Michael

• Engineering
• Energy
• Civil Engineering

Statement dc:rights

• unrestricted
• This thesis or dissertation is protected by copyright: some rights reserved. It is licensed for use under a Creative Commons license. Specific terms and permissions are available from this document's record in the OhioLINK ETD Center.

Language dc:language

English

Repository record dc:identifier

http://rave.ohiolink.edu/etdc/view?acc_num=case1364832753

OAI identifier oai:identifier

oai:etd.ohiolink.edu:case1364832753