Extracting full-field dynamic strain on a wind turbine rotor subjected to arbitrary excitations using 3D point tracking and a modal expansion technique

In the current work, the optical three-dimensional point-tracking (3DPT) measurement approach is used in conjunction with a recently developed modal expansion technique. These two approaches (empirical and analytical) complement each other and enable the prediction of the full-field dynamic response on the surface of the structure as well as within the interior points. The practical merit of the approach was verified using a non-spinning and spinning wind turbine rotor. The three-bladed wind turbine rotator was subjected to different loading scenarios and the displacement of optical targets located on the blades was measured using 3DPT. The measured displacement was expanded and applied to the finite element model of the turbine to extract full-field strain on the turbine. The sensitivity of the proposed approach to the number of optical targets was studied in this paper. It is shown the approach can accurately predict the strain even with very few set of measurement points.

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Predicting full-field dynamic strain on a three-bladed wind turbine using three dimensional point tracking and expansion techniques

10.1117/12.2046106 ◽

2014 ◽

Cited By ~ 1

Author(s):

Javad Baqersad ◽

Christopher Niezrecki ◽

Peter Avitabile

Keyword(s):

Wind Turbine ◽

Three Dimensional ◽

Dynamic Strain ◽

Full Field ◽

Point Tracking ◽

Field Dynamic

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A Noncontacting Approach for Full-Field Strain Monitoring of Rotating Structures

Journal of Vibration and Acoustics ◽

10.1115/1.4032721 ◽

2016 ◽

Vol 138 (3) ◽

Cited By ~ 24

Author(s):

Javad Baqersad ◽

Peyman Poozesh ◽

Christopher Niezrecki ◽

Peter Avitabile

Keyword(s):

Three Dimensional ◽

Turbine Rotor ◽

Field Strain ◽

Dynamic Strain ◽

Fe Model ◽

Fe Method ◽

Full Field ◽

Modal Expansion ◽

Point Tracking ◽

Measurement Approach

The three-dimensional point-tracking (3DPT) measurement approach is used in conjunction with finite element (FE) method and modal expansion technique to predict full-field dynamic response on a rotating structure. A rotating three-bladed wind turbine rotor was subjected to different loading scenarios, and the displacement of optical targets located on the blades was measured using 3DPT. The out-of-plane measured displacement of the targets was expanded and applied to the FE model of the turbine to extract full-field strain on the turbine. The sensitivity of the proposed approach to the number of optical targets was also studied in this paper. The results show that the dynamic strain on a structure can be extracted with a very limited set of measurement points (optical targets) placed on appropriate locations on the blades. It was shown that the proposed technique is able to extract dynamic strain all over the entire structure, even inside the structure beyond the line of sight of the measurement system. Because the method is based on a noncontacting measurement approach, it can be readily applied to a variety of structures having different boundary conditions.

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