Measurement of in-plane thermal diffusivity of solids moving at constant velocity using laser spot infrared thermography

Bedoya, A.; González, Jorge Méndez; Rodríguez‐Aseguinolaza, Javier; Mendioroz, A.; Sommier, Alain; Batsale, Jean Christophe; Pradère, Christophe; Salazar, A.

doi:10.1016/j.measurement.2018.11.013

Cited by 24 publications

(16 citation statements)

References 15 publications

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“…The proposed approach utilizes step-like temporal profile of point local heating of the surface by laser beam with Gauss radius r 0 = 0.1-0.3 mm and simultaneous filming of transient temperature field induced by this heating at the object surface by an IR camera. In our experiments, laser heating has constant power during all testing time (step-heating thermography) like [69][70][71][72] whereas classic LFT uses short pulse heating [44,[58][59][60][61][62][63][64][65][66]. It significantly reduced the temperature in the hot spot, while increasing it in the surrounding inspected area and lowering requirements to laser output power.…”

Section: Methodsmentioning

confidence: 99%

“…Further advances in LFT result in variants employing thermal wave propagation not only in normal direction as in classic LFT [41], but also in plane techniques [44,[58][59][60][61][62]. It uses point heating to implement the radial diverging thermal wave technique for immobile objects [44,[58][59][60][61] and for moving ones [62]. Heating from ring-shaped area in the radial converging thermal wave technique provides better signal/noise ratio and reduces overheating in the irradiated area [63][64][65][66][67].…”

Section: Introductionmentioning

confidence: 99%

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Temperature Diffusivity Measurement and Nondestructive Testing Requiring No Extensive Sample Preparation and Using Stepwise Point Heating and IR Thermography

Golovin¹,

Divin²,

Samodurov³

et al. 2019

Failure Analysis

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This chapter describes a modification to the laser flash method that allows determining temperature diffusivity and nondestructive testing of materials and constructions without cutting samples of predefined geometry. Stepwise local heating of the studied object surface at a small spot around 0.1 mm radius with simultaneous high temporary-spatial resolution infrared (IR) filming of the transient temperature distribution evolution with a thermal camera provides a wide range of possibilities for material characterization and sample testing. In case of isotropic and macroscopic homogeneous materials, the resulting transient temperature distribution is radially symmetric that renders possible to improve temperature measurement accuracy by averaging many pixels of the IR images located at the same distance from the heating spot center. The temperature diffusivity measurement can be conducted either on thin plates or on massive samples. The developed emissivity independent in plain IR thermographic method and mathematical algorithms enable thermal diffusivity measurement for both cases with accuracy around a few per cent for a wide range of materials starting from refractory ceramics to well-conducting metals. To detect defects, the differential algorithm was used. Subtracting averaged radial symmetric temperature distribution from the original one for each frame makes local inhomogeneities in the sample under study clearly discernible. When applied to crack detection in plates, the technique demonstrates good sensitivity to part-through cracks located both at the visible and invisible sides of the studied object.

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Section: Methodsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Temperature Diffusivity Measurement and Nondestructive Testing Requiring No Extensive Sample Preparation and Using Stepwise Point Heating and IR Thermography

Golovin¹,

Divin²,

Samodurov³

et al. 2019

Failure Analysis

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show abstract

“…Once the projected coordinates on the parallel screen under O-XYZ coordinate system— A 1 ( x A 1 , y A 1 , z A 1 ), A 2 ( x A 2 , y A 2 , z B 2 ), B 1 ( x B 1 , y B 1 , z B 1 ), and B 2 ( x B 2 , y B 2 , z A 2 )—are determined, there is a unique space target position coordinate ( x , y , z ) corresponding to them. Mathematically, the accurate projected coordinates can be manifested as the centroid coordinates and the target precision depends on the precision of the projected coordinates [ 27 , 28 ].…”

Section: Related Workmentioning

confidence: 99%

Least-Square-Method-Based Optimal Laser Spots Acquisition and Position in Cooperative Target Measurement

Feng

et al. 2022

Sensors

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The relative positioning precisions of coordinate points is an important indicator that affects the final accuracy in the visual measurement system of space cooperative targets. Many factors, such as measurement methods, environmental conditions, data processing principles and equipment parameters, are supposed to influence the cooperative target’s acquisition and determine the precision of the cooperative target’s position in a ground simulation experiment with laser projected spots on parallel screens. To overcome the precision insufficiencies of cooperative target measurement, the factors of the laser diode supply current and charge couple device (CCD) camera exposure time are studied in this article. On the hypothesis of the optimal experimental conditions, the state equations under the image coordinates’ system that describe the laser spot position’s variation are established. The novel optimizing method is proposed by taking laser spot position as state variables, diode supply current and exposure time as controllable variables, calculating the optimal controllable variables through intersecting the focal spot centroid line and the 3-D surface, and avoiding the inconvenience of solving nonlinear equations. The experiment based on the new algorithm shows that the optimal solution can guarantee the focal spot’s variation range in 5–10 pixels under image coordinates’ system equivalent to the space with a 3 m distance and 0.6–1.2 mm positioning accuracy.

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“…η da laginak xurgatutako energia-frakzioa, µ = 4Dt da hedapen termikoaren luzera, erf da errorearen funtzioa, u = y + y o , K, D eta e dira, hurrenez hurren, eroankortasun termikoa, difusibitate termikoa eta efusibitate termikoa. Rth da pitzadurarekin lotutako erresistentzia termikoa, eta L pitzaduraren zabalerarekin R th = L / Kair [12] ekuazioaren bidez erlazionatuta dago.…”

Section: Garapen Teorikoaunclassified

Pitzadura bertikalen detekzio eta karakterizazioa termografia infragorria eta laser mugikorra erabiliz

Apiñaniz

Salazar

Oleaga

et al. 2020

EKAIA

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Artikulu honetan, termografia infragorri aktiboaren bidez, pieza handietako pitzadura bertikalak karakterizatzeko metodo bat aurkeztuko dugu. Metodo honen bidez materialaren gainazala abiadura konstantez mugitzen den laser sorta batekin argiztatzen dugu, eta abiadura handiko kamera infragorri bat erabiliz gainazaleko tenperaturaren aldaketaren garapena neurtzen dugu. Gainazaleko pitzadura bertikalak uhin termikoentzat hesi termiko bat dira, eta, beraz, gainazaleko tenperaturaren profilean ez-jarraitasun bat sortzen dute. Matematikoki garatutako modelo teorikoa esperimentalki lortutako tenperatura profilarekin doituz, pitzaduraren ezaugarriak lor ditzakegu. Garatutako metodoa baliozkoa da laser sorta mugitu beharrean laserra geldi utzi eta lagina mugitzen dugunean; azken hori interesgarria da ekoizpen-kateetan pitzadurak in situ karakterizatu ahal izateko. Lan honetan, beraz, gure ikerketa taldeak pitzadura bertikalak karakterizatu ahal izateko jarraitutako ibilbidea azalduko dugu, eta lortutako metodoa balioztatzeko kalibratutako laginekin egindako neurketak aurkeztuko ditugu.

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Measurement of in-plane thermal diffusivity of solids moving at constant velocity using laser spot infrared thermography

Cited by 24 publications

References 15 publications

Temperature Diffusivity Measurement and Nondestructive Testing Requiring No Extensive Sample Preparation and Using Stepwise Point Heating and IR Thermography

Temperature Diffusivity Measurement and Nondestructive Testing Requiring No Extensive Sample Preparation and Using Stepwise Point Heating and IR Thermography

Least-Square-Method-Based Optimal Laser Spots Acquisition and Position in Cooperative Target Measurement

Pitzadura bertikalen detekzio eta karakterizazioa termografia infragorria eta laser mugikorra erabiliz

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