04/09/2021
By Sokny Long

The Francis College of Engineering, Department of Mechanical Engineering, invites you to attend a Master’s thesis defense by Natalie Diltz on “Monitoring and Assessment of Wind Turbine Foundation Degradation.”

MSE Candidate: Natalie Diltz
Defense Date: Wednesday, April 21, 2021
Time (from/to): 9 to 10 a.m. EST
Location: This will be a virtual defense via Zoom. Those interested in attending should contact Natalie_Diltz@student.uml.edu and committee advisor, Christopher_Niezrecki@uml.edu, at least 24 hours prior to the defense to request access to the meeting.

Committee Chair (Advisor): Christopher Niezrecki, University Professor and Department Chair, Mechanical Engineering, University of Massachusetts Lowell

Committee Members:

  • Peter Avitabile, Professor Emeritus, Mechanical engineering, University of Massachusetts Lowell
  • Pradeep Kurup, Professor and Department Chair, Civil and Environmental Engineering, University of Massachusetts Lowell

Brief Abstract:

Wind Turbine Foundations account for only 1.5% of the total turbine failures, however they often result in catastrophic damage and total loss of the turbine. There are multiple types of failures that can befall a turbine and this research is focused on Anchorage cone – pullout failure, which is the combination of downward and upward flexural failure in gravity spread foundations. Cracking is a precursor to total turbine failure that weakens the foundation stiffness leading to overall degradation. Imperfections in the construction of the foundation can lead to crack propagation, which is exasperated by the regular cyclical loading the turbine experiences. It is important to diagnose cracking early as damage compounds with time and current diagnostic methods are invasive and expensive. Research dedicated to crack monitoring has focused on localized linear cracking.

The purpose of this research was to assess utilizing existing or low-cost sensors to identify when stiffness changes occur in the foundation, indicating damage or crack growth. A Finite Element Model (FEM) was developed in FEMAP using the turbine manufacturing specs from GE and then validated for accuracy. Eigenvalue analysis identified modal displacements and frequencies at the tower top where sensors would be placed. The stiffness line of the Frequency Response Function (FRF) was then determined from these inputs to better assess the stiffness behavior of the foundation. The results showed that the FRF is dominated by the tower behavior because the tower is much more flexible than the soil and foundation. Ultimately, more work is required with experimentally derived data in a practical installation to determine if this approach can be viable.

All interested students and faculty members are invited to attend the online defense via remote access.