Funding:

• • National Science Foundation

Collaborators:

• • Mark Rumsey, Sandia National Laboratory Wind Power Technologies Department

  • Dennis Roach, Sandia National Laboratory

  • Prof. William Kuperman, UCSD Scripps Institution of Oceanography

Purpose:

To develop a structural health monitoring system for defect detection and defect imaging in composite wind turbine blades. To develop NDE standards for composite blades. To provide damping of unwanted vibrations in the blades. 

Synopsis:

The performance of a wind turbine is driven by several factors. One critical factor is, of course, structural integrity. Structural defects in the blades can be introduced during the blade’s manufacturing process, or generated in service by, for example, vibration-induced fatigue. As a primary component of the turbine, the rotor blades are built to withstand many fatigue cycles during their lifetime, which can exceed that of a typical bridge or commercial aircraft. Complicating the design requirements even further are the highly stochastic wind conditions that drive the rotor blades.

The research at UCSD is focused on studying systems able to (1) detect and image structural defects in the blades, and (2) mitigate unwanted vibrations in the blades to minimize fatigue exposure.  The defect detection and imaging approach is focused on the exploitation of passive wave fields to reconstruct a high-frequency Green’s function between sensor positions. The passively-reconstructed Green’s functions are further analyzed through Matched-Field-Processing techniques to obtain a defect map (image).  Reciprocity techniques are also utilized to detect damage between two sensors from the passively reconstructed Green’s functions.  As a complement to the wave approach, statistically-enhanced Infrared Thermography is being applied to the defect detection in the blades. For vibration mitigation, shunt damping from Macro-Fiber Composite (MFC) patches is being studied.

Selected Publications:

Tippmann, J. and Lanza di Scalea, F., “Passive-Only Damage Detection by Reciprocity of Green’s Functions Reconstructed from Diffuse Acoustic Fields with Application to Wind Turbine Blades,” Journal of Intelligent Material Systems and Structures, 26(10), pp. 1251-1258, 2015. 

Tippmann, J., Zhu, P., and Lanza di Scalea, F.,” Application of Damage Detection Methods Using Passive Reconstruction of Impulse Response Functions,” Philosophical Transactions of the Royal Society A – Mathematical, Physical and Engineering Sciences, Special Issue on New Perspectives in Offshore-Wind and Sea-Wave Energy Production, 373(2035), pp. 1-17, 2015. 

Tippmann, J. and Lanza di Scalea, F., “Structural Health Monitoring of Composite Wind Turbine Blades Using Diffuse Ultrasonic Fields and Reciprocity,” Proceedings of the American Society for Composites 29th Technical Conference and 16th US-Japan Conference on Composite Materials, San Diego, CA, Sept 8-10, pp. 1-11, 2014.

Tippmann, J., Zhu, X. and Lanza di Scalea, F., “Probabilistic Structural Health Monitoring Using Passive-Only Damage Detection by Reciprocity of Green’s Functions Reconstructed from Diffuse Acoustic Fields,” CD-ROM Proceedings of the 7th European Workshop on Structural Health Monitoring, (EWSHM 2014), Nantes, France, July 8-11, pp. 1-8, 2014.

Tippmann J. and Lanza di Scalea, F., “Structural Health Monitoring Of Composite Wind Turbine Blades Using Coherent Guided Waves From Diffuse Fields,” Proceedings of the 2013 ASME International Mechanical Engineering Congress and Exposition (IMECE 2013), San Diego, CA, November 15-21, 2013.

Tippmann, J. and Lanza di Scalea, F., “Using Diffuse Fields For Monitoring The Structural Health Of Wind Turbine Blades,” Structural Health Monitoring 2013 – A Roadmap to Intelligent Structures – Proceeding of the 9th Intl Workshop on Structural Health Monitoring, F-K. Chang, ed., Stanford University, pp. 2369-2375, Sept. 10-12, 2013.

Tippmann, J. and Lanza di Scalea, F., “Vibration control experiments using piezoelectric transducers on a wind turbine blade at UC San Diego,” Proceedings of SPIE (International Society for Optical Engineering) Smart Structures/NDE Annual International Symposium – Sensors and Smart Structures Technologies for Civil, Mechanical, and Aerospace Systems, P. Lynch, C-B. Yun, K-W Wang, eds., San Diego, CA, March 10-14, Vol. 8692, pp. 86921H1-86921H8, 2013.

Tippmann, J., Manohar, A., and Lanza di Scalea, F., “Wind Turbine Blade Inspection Tests At UCSD”, Proceedings of SPIE (International Society for Optical Engineering) Smart Structures/NDE Annual International Symposium – Sensors and Smart Structures Technologies for Civil, Mechanical, and Aerospace Systems, M. Tomizuka, ed., San Diego, CA, March 11-15, Vol. 8345, 2012.