Shape estimation and health monitoring of wind turbine tower using a FBG sensor array

Bang, Hyung-Joon; Suk-Whan, Ko; Jang, Moon-Seok; Kim, Hongil

doi:10.1109/i2mtc.2012.6229407

Cited by 24 publications

(24 citation statements)

References 6 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…These features distinguish the developed method from other existing model-augmented dynamic strain measurements using only a limited set of measurements (accelerometers, strain gauges, OFS, or optical markers). [52][53][54][55][56][57][58][59][60][61][62][63] Laboratory experiments were conducted to validate the method on a bench-scale cantilever beam structure. Results demonstrate that the full-field dynamic strains estimated by the developed approach from the video measurement of the output-only vibrating beam match very well those directly measured by strain gauges (at discrete measurement points).…”

Section: Introductionmentioning

confidence: 99%

Estimation of full‐field dynamic strains from digital video measurements of output‐only beam structures by video motion processing and modal superposition

Yang

Jung

Dorn

et al. 2019

Struct Control Health Monit

View full text Add to dashboard Cite

Summary Strain is an essential quantity to characterize local structural behaviors and directly correlates with structural damage initiation and development that is within local regions. Strain measurement at high spatial resolution (density) locations is thus required to characterize local structural behaviors and detect potential local damage. Traditional contact‐type strain gauges are mostly discrete point‐wise sensors that can only be placed in a limited number of positions. Distributed optical fiber sensing techniques can measure strains at spatially dense measurement points, but their instrumentation is a time‐ and labor‐intensive process associated with the issue of the fragility of fibers. Noncontact optical measurement techniques, such as a family of interferometry techniques using laser beams (e.g., laser Doppler vibrometers), can provide vibration measurement at high density spatial points without the need to install sensors on the structure. However, these measurement devices are active sensing methods that are relatively expensive and vulnerable to ambient motion. Photogrammetry is an alternative noncontact optical measurement method using (passive) white‐light imaging of digital video cameras that are relatively low‐cost, agile, and provides simultaneous measurements at high spatial density locations where every pixel becomes a measurement point. Among others, digital image correlation can achieve full‐field deformation measurements and subsequently estimate the full‐field strains. However, it is computationally extensive. This study develops a new efficient approach to estimate the full‐field (as many measurement points as the pixel number of the video frame on the structure) dynamic strains at high‐spatial (pixel)‐resolution/density location points from the digital video measurement of output‐only vibrating structures. The developed approach is based on phase‐based video motion estimation and modal superposition of structural dynamic response. Furthermore, the method is augmented by a high‐fidelity finite element model, which is updated with the full‐field experimental modal parameters “blindly” identified from the video measurement of the output‐only structure. Laboratory experiments are conducted to validate the method on a bench‐scale cantilever beam structure. Results demonstrate that the full‐field dynamic strain estimated by the developed approach from the video measurement of the output‐only vibrating beam match very well those directly measured by the strain gauges (at discrete measurement points). Some factors associated with the effectiveness of the method are experimentally studied and discussed.

show abstract

Section: Introductionmentioning

confidence: 99%

Estimation of full‐field dynamic strains from digital video measurements of output‐only beam structures by video motion processing and modal superposition

Yang

Jung

Dorn

et al. 2019

Struct Control Health Monit

View full text Add to dashboard Cite

show abstract

“…After that, modal approach was gradually developed by many researchers [14][15][16][17][18][19] and was widely used in predicting the displacement of structure. [20][21][22][23][24][25][26] The principle of modal approach is founded on strain and displacement modes extracted from finite element method (FEM) simulation. As strains of structure are acquired, displacement vector can be deduced with transformation matrix multiplying strain vector.…”

Section: Introductionmentioning

confidence: 99%

Strain‐based displacement field reconstruction method for thin rectangular plate through orthogonal deflection curves bridging

Luo

Gao

et al. 2019

Struct Control Health Monit

View full text Add to dashboard Cite

Summary In the existing studies of strain‐based displacement field detection for thin rectangular plate, either the boundary conditions are too difficult to handle or the sensors layout and algorithm computing process are too complex to satisfy the requirement of rapid reconstruction of nonlinear vibration shape. In this paper, a strain‐displacement conversion method for reconstructing the deformed shape of rectangular plate with typical boundary conditions is presented. This method overcomes the above shortcomings for small deflection nonlinear vibration in linear elastic range. Strains measuring points are uniformly and regularly distributed in the middle area of the plate. Unmeasurable boundary strains will be estimated using the new derived formula according to quadratic interpolation of strains and boundary conditions. The principle of the proposed method is to bridge the orthogonal deflection curves by translating and rotating them. In this way, framework of displacement field can be formed. First, curvature integral method is employed to shape the orthogonal deflection curves of deformed plate. Then, the rotating angles and translating displacements are deduced according to boundary conditions. For some special boundary plates, it even needs to solve nonlinear optimization problem to get the rotating angles. The displacement field reconstructed by the proposed method shows great agreement with the finite element analyses results, which verifies the effectiveness of the methodology.

show abstract

“…Most of the methods based on the integration of measured strains deal with beam problems and make use of the classical beam equations [2,3]. For the full-field estimation of the deformed shape of more complex two-dimensional structures, basis-function approaches utilize an a priori set of spatial functions and unknown coefficients to fit discretely measured strains [4][5][6][7][8]. A major drawback of the methods based on neural networks is that their accuracy depends on the choice of the training load cases [9].…”

Section: Introductionmentioning

confidence: 99%

Shape Sensing of Plate and Shell Structures Undergoing Large Displacements Using the Inverse Finite Element Method

Tessler

Roy

Esposito

et al. 2018

Shock and Vibration

View full text Add to dashboard Cite

The inverse Finite Element Method (iFEM) is applied to reconstruct the displacement field of a shell structure which undergoes large deformations using discreet strain measurements as the prescribed data. The iFEM computations are carried out using an incremental procedure where at each load step, the incremental strains are used to evaluate the incremental displacements which in turn update the geometry of the deformed structure. The efficacy of the proposed approach to predict large displacements is examined using two case studies involving a cantilevered wing-shaped plate and a clamped plate. The incremental iFEM procedure is demonstrated to be sufficiently accurate in terms of reproducing the correct nonlinear character of the load-displacement curve even when a reduced number of strain sensors is used. Therefore, this approach may have important implications for real-time monitoring of aerospace structures that undergo large displacements.

show abstract

Shape estimation and health monitoring of wind turbine tower using a FBG sensor array

Cited by 24 publications

References 6 publications

Estimation of full‐field dynamic strains from digital video measurements of output‐only beam structures by video motion processing and modal superposition

Estimation of full‐field dynamic strains from digital video measurements of output‐only beam structures by video motion processing and modal superposition

Strain‐based displacement field reconstruction method for thin rectangular plate through orthogonal deflection curves bridging

Shape Sensing of Plate and Shell Structures Undergoing Large Displacements Using the Inverse Finite Element Method

Contact Info

Product

Resources

About