Measurement of the external parameters in quantitative active thermography

Olmi, Roberto; Inglese, Gabriele

doi:10.1088/1361-6501/aa7ce1

Cited by 5 publications

(3 citation statements)

References 22 publications

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“…Active infrared (IR) thermography with thermal excitation sources is a contactless, visualization and nondestructive detection technique that has been widely used for the depth detection of defects [3,4]. According to the type of thermal excitation source, active IR thermography can be classified into several common methods, such as pulsed thermography (PT), lock-in thermography (LIT), and step-heating thermography (SHT) [5][6][7].…”

Section: Introductionmentioning

confidence: 99%

Depth detection of spar cap defects in large-scale wind turbine blades based on a 3D heat conduction model using step heating infrared thermography

Zhang¹,

Zhou²,

Li³

et al. 2022

Meas. Sci. Technol.

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The defects dispersed in spar cap often lead to failure of large-scale wind turbine blades. To predict the residual service life of blade and make repair, it is necessary to detect the depth of spar cap defects. Step-heating thermography (SHT) is a common infrared technique in this domain. However, the existing methods of SHT on defect depth detection are generally based on 1D models, which are unable to accurately detect the depth of spar cap defects because of ignoring material anisotropy and in-plane heat flow. To improve the depth detection accuracy of spar cap defects, a 3D model based on the theory of heat transfer is established by using equivalent source method (ESM), and a defect depth criterion is proposed based on the analytical solution of heat conduction equation. The modeling process are as follows. The heat conduction model of SHT was established by ESM. Then, coordinate transformation, variables separation and Laplace transformation were utilized to solve the 3D heat conduction equation. A defect depth criterion was proposed based on emerging contrast Cr. A GFRP composites plate containing 12 square flat-bottom holes with different sizes and depths was manufactured to represent spar cap with large thermal resistance defects, such as Delamination and crack. Experimental results demonstrate the validity of 3D model. Then the model was applied to on-site SHT test of a 1.5 megawatts (MW) wind turbine blade. The test results prove that the depth detection accuracy of spar cap defects can be significantly improved by using 3D model. In addition, by using a improved principle component analysis (PCA) method containing contrast enhancement factor, artifacts can be reduced and the recognition time of defects can be shortened.

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Section: Introductionmentioning

confidence: 99%

Depth detection of spar cap defects in large-scale wind turbine blades based on a 3D heat conduction model using step heating infrared thermography

Zhang¹,

Zhou²,

Li³

et al. 2022

Meas. Sci. Technol.

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“…In this paper, we present selected results obtained on masonry bridges by using the thermographic technique [6] and their integration in the TOSCA-FI platform.…”

Section: Introductionmentioning

confidence: 99%

Integrating Thermographic Images in A User-Friendly Platform to Support Inspection of Railway Bridges

Olmi

Palombi

Durazzani³

et al. 2019

The 15th International Workshop on Advanced Infrared Technology and Applications

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preventive inspection of railway bridges is a key step for an effective maintenance program. The TOSCA-FI project has developed an integrated ICT platform for easy access to a wide set of data, obtained with several imaging techniques (high definition photography, photogrammetry, 3D scanning, fluorescence LIDAR and thermography) and integrated into a 3D model of the bridge. The aim is to provide a tool to support the inspection of railway bridges, often based exclusively on the visual inspection. In this paper, we present selected results obtained on masonry bridges by using thermography and their integration in the TOSCA-FI platform.

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“…Based on the characteristics of the materials, halogen lamps [52], ultraviolet radiation, flash [53], lasers or infrared lamps can be used as heat source. Active IRT has also been used in many situations to investigate building materials and their defects [54,55] through the quantitative analysis of transient thermal data [52,56,57].…”

Section: Introductionmentioning

confidence: 99%

A discussion concerning active infrared thermography in the evaluation of buildings air infiltration

Lerma

Barreira

Almeida

2018

Energy and Buildings

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The EU is strongly committed to energy saving in buildings. Air leaks through the building envelope represent a significant percentage of buildings energy consumption. Locating and minimizing air leaks is thus necessary to optimize energy efficiency. This work presents the results of an experimental campaign that aimed to promote a discussion concerning the opportunities and constraints of using active IRT to detect air leakage points. The potential of active IRT was evaluated both in a qualitative approach, by comparing the thermograms with the ones obtained with passive IRT, and in a quantitative one, by testing methods of numerically interpret the thermograms. The results allowed concluding that active IRT increases the thermal contrast and the affected area, proving that active IRT combined with pressure differences is an effective methodology for detecting air infiltrations. In the quantitative approach different numerical methods can be used. Their selection depends on the aims of the study, as they can highlight different perspectives of the phenomenon.

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Measurement of the external parameters in quantitative active thermography

Cited by 5 publications

References 22 publications

Depth detection of spar cap defects in large-scale wind turbine blades based on a 3D heat conduction model using step heating infrared thermography

Depth detection of spar cap defects in large-scale wind turbine blades based on a 3D heat conduction model using step heating infrared thermography

Integrating Thermographic Images in A User-Friendly Platform to Support Inspection of Railway Bridges

A discussion concerning active infrared thermography in the evaluation of buildings air infiltration

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