Defect localization based on modulated photothermal local approach

Lascoup, Bertrand; Perez, Laetitia; Autrique, Laurent

doi:10.1016/j.compositesb.2013.12.012

Cited by 7 publications

(6 citation statements)

References 17 publications

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“…The early detection of these defects is beneficial to the structural integrity and maintenance. Different methods have been exploited in recent years, including pulse-thermography [4], ultrasonic [5], X ray, acoustic emission [6,7], and electric resistance variation [8,9]. Among all these methods, ultrasonic testing is considered to be promising for in-situ or online inspection.…”

Section: Introductionmentioning

confidence: 99%

Experimental Study of Defect Localization in a Cross-Ply Fiber Reinforced Composite with Diffuse Ultrasonic Waves

Zhu

Ding

et al. 2019

Applied Sciences

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Diffuse wave inspection benefits from multiple scattering and is suitable for the nondestructive testing of complex structures with high sensitivity. This paper aims to localize the defect in a cross-ply carbon fiber reinforced polymer composite with the diffuse wave field experimentally based on the Locadiff technique. Firstly, the wave diffusivity and dissipation parameters are determined from the diffuse waveforms. Great dissipation is found for this composite plate due to its strong viscoelasticity, which makes the amplitude attenuate fast in a short propagation distance. The signal-to-noise ratios degrade significantly at off-axis directions so that only measurements along the X and Y axes are chosen. Secondly, the decorrelation coefficients are determined using the stretching technique. The decorrelation coefficients decrease initially due to the interaction between the wave fields and the defect and subsequently increase due to the low signal-to-noise ratio at the later time. Based on these data, a sensitivity time domain is chosen to center at t = 50 μs. Together with the defect sensitivity kernel calculated under constant diffusion property assumption, the defect is localized at [270 mm, 265 mm] compared to [300 mm, 280 mm] in the final reference state. This method is promising for early damage detection in fiber reinforced composite structures.

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Section: Introductionmentioning

confidence: 99%

Experimental Study of Defect Localization in a Cross-Ply Fiber Reinforced Composite with Diffuse Ultrasonic Waves

Zhu

Ding

et al. 2019

Applied Sciences

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“…Once again, the primary difference between the work described there and the present method is the determination of thermal properties and the use of other fitting functions. Another modulating heat source was used by Lascoup et al [9] to locate material defects. This work continued the efforts started in Reference [6] but concentrated on an approach for finding small defects over a very small area.…”

Section: Introductionmentioning

confidence: 99%

“…This work continued the efforts started in Reference [6] but concentrated on an approach for finding small defects over a very small area. Necsulescu et al [10] used a sinusoidal heating system much like References [6,9] and Mulaveesala [11] and Arora [12] where oscillating heating sources were used. This is unlike the constant-intensity scanning heat source presented in the current research.…”

Section: Introductionmentioning

confidence: 99%

“…These involved areas of low thermal resistance indicating the breakdown the of bonding of the thermal protection system tiles in spacecraft. The objective of Reference [16] is similar to the delamination studies presented in References [3,6,9] but used laser pulses as the primary heating source. In contrast to the specialized application of these methods, the research presented herein is aimed at finding any type of defect or void, either within a material or on the surface.…”

Section: Introductionmentioning

confidence: 99%

“…In contrast to the specialized application of these methods, the research presented herein is aimed at finding any type of defect or void, either within a material or on the surface. Another compositematerial NDT method was presented by Vavilov [18] which was much like References [6,15,9,7]. El Ballouti and Belattar [19] dealt with adhesion between layers, much like References [3,6], except that material under investigation was used for roadways.…”

Section: Introductionmentioning

confidence: 99%

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Detecting Material Defects Using a Scanning Laser Beam

McMasters

Brooke

David

et al. 2019

Journal of Thermophysics and Heat Transfer

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Thermal methods have been used in non-destructive testing as part of the collection of many techniques available for finding flaws in various materials. Although several types of Thermal Non-Destructive Testing (TNDT) are used on composite materials, the work presented as part of the present research is focused on plate steel samples. Defects are introduced on a steel sample prior to the start of the experiment and a scanning-laser TNTD method is used in an effort to find the defect locations. A moving line-source laser beam was utilized in an effort to scan the entire surface of a rectangular plate, pursuant to locating defects. In order to reconfigure a point beam of laser energy into a line-heating source, sheetforming optical components were used. Efforts were made to form the beam such that the intensity of the line-heating source would be as uniform as possible. The heat source was then scanned across the sample by placing the sample in a vertical position on a moving servo table which moved horizontally at a prescribed speed of 1 mm/s. This speed was chosen to allow the laser to be utilized at maximum power so as to generate the largest possible temperature gradient without exceeding a temperature rise of ten degrees centigrade. The large temperature gradient was desired in order to maximize the sensitivity of the defect-detection method, since the method of detection hinges on the principle that mechanical defects in the material generate perturbations in the measured temperature field. The relatively-small overall temperature rise of ten degrees is desired in order to allow the heat transfer to be modelled mathematically assuming constant thermal properties. A thermal camera was used for recording the temperature distribution on the non-heated side of the sample, and for this experiment, the camera used was the FLIR 8000. A series of ten images was recorded as the sample was scanned with the laser. Each image was fitted with a mathematical model. Although the thermal diffusivity of the sample is often ostensibly known, thermal diffusivity was treated as one of the unknown parameters in the fitting process. This is because there can be a variation in thermal diffusivity values within a collection of samples of a given type of materials. Moreover, the use of an accurate thermal diffusivity value in the mathematical model has a significant influence on the adequacy of the fit to the experimental data. Once the mathematical model is fitted to the experimental data by varying the thermal diffusivity and the shape of the heat flux, the calculated temperature is subtracted from the measured temperature and a residual temperature field is created. From looking at aberrations and anomalies in this residual temperature field, defects can be found by visual inspection of the residual temperature field image. As an additional feature of this research, the method of model-fitting is compared with a method involving simple spline fits and with the Mollification Method in terms of effectiveness.

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A model‐based failure times identification for a system governed by a 2D parabolic partial differential equation

Bidou,

Perez,

Verron

et al. 2024

IET Control Theory & Appl

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This research focuses on the identification of failure times in thermal systems governed by partial differential equations, a task known for its complexity. A new model‐based diagnostic approach is presented that aims to accurately identify failing heat sources and accurately determine their failure times, which is crucial when multiple heat sources fail and there is a delay in detection by distant sensors. To validate the effectiveness of the approach, a comparative analysis is carried out with an established method based on a Bayesian filter, the Kalman filter. The aim is to provide a comprehensive analysis, highlighting the advantages and potential limitations of the methodology. In addition, a Monte Carlo simulation is implemented to assess the impact of sensor measurements on the performance of this new approach.

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Defect localization based on modulated photothermal local approach

Cited by 7 publications

References 17 publications

Experimental Study of Defect Localization in a Cross-Ply Fiber Reinforced Composite with Diffuse Ultrasonic Waves

Experimental Study of Defect Localization in a Cross-Ply Fiber Reinforced Composite with Diffuse Ultrasonic Waves

Detecting Material Defects Using a Scanning Laser Beam

A model‐based failure times identification for a system governed by a 2D parabolic partial differential equation

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