Remote measurement of in-plane diffusivity components in plates

Welch, Christopher S.; Heath, D. Michele; Winfree, William P.

doi:10.1063/1.338140

Cited by 34 publications

(11 citation statements)

References 8 publications

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“…In order to determine the in plane diffusivities in two directions parallel and perpendicular to the fiber orientation of the first surface layer of the sample, the sample surface was heated locally using a laser line [13]. Using a line heating source instead of a spot source [14], which is frequently used, enables to average the signal along the length of the line -thus averaging along probably varying surface properties of the specimen.…”

Section: Experimental Methodsmentioning

confidence: 99%

Determining the material parameters for the reconstruction of defects in carbon fiber reinforced polymers from data measured by flash thermography

Müller¹,

Götschel²,

Maierhofer³

et al. 2017

AIP Conference Proceedings

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Abstract. Flash thermography is a fast and reliable non-destructive testing method for the investigation of defects in carbon fiber reinforced polymer (CFRP) materials. In this paper numerical simulations of transient thermography data are presented, calculated for a quasi-isotropic flat bottom hole sample. They are compared to experimental data. These simulations are one important step towards the quantitative reconstruction of a flaw by assessing thermographic data. The applied numerical model is based on the finite-element method, extended by a semi-analytical treatment of the boundary of the sample, which is heated by the flash light. A crucial part for a reliable numerical model is the prior determination of the material parameters of the specimen as well as of the experimental parameters of the set-up. The material parameters in plane and in depth diffusivity are measured using laser line excitation. In addition, the absorption and heat transfer process of the first layers is investigated using an IR microscopic lens. The performance of the two distinct components of CFRP during heating -epoxy resin and carbon fibers -is examined. Finally, the material parameters are optimized by variation and comparison of the simulation results to the experimental data. The optimized parameters are compared to the measured ones and further methods to ensure precise material parameter measurements are discussed.

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Section: Experimental Methodsmentioning

confidence: 99%

Determining the material parameters for the reconstruction of defects in carbon fiber reinforced polymers from data measured by flash thermography

Müller¹,

Götschel²,

Maierhofer³

et al. 2017

AIP Conference Proceedings

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show abstract

“…For this purpose, different experimental configurations and data processing procedures have been proposed in the past . Heat can be applied over a point [7][8][9][10][11][12], a Gaussian distribution (spot or strip) [13,14], a disk area [15,16], an annular area [16,17], a line or a strip [18][19][20][21], a half plane [22], or a square corner [23]. Recently it was also suggested to use a moving line heat source [24] or a heat pulse with random distribution [25].…”

Section: Introductionmentioning

confidence: 99%

Measurement of in-plane diffusivity in non-homogeneous slabs by applying flash thermography

Krapez

Spagnolo

Frieß

et al. 2004

International Journal of Thermal Sciences

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“…While there are techniques/instrumentation for x-ray tomography and laminography, these are currently too expensive and time consuming. With thermography, material properties related to the rate of temperature change-such as thermal diffusivity-are significant rather than the absolute temperature [8], [9]. Thus, the impact of factors such as emissivity, array detector sensitivity variation, etc., which introduce error in absolute temperature determinations are reduced.…”

Section: Background Of the Problemmentioning

confidence: 99%

Thermographic Characterization of Feal Green Sheet

Hinders

Watkins²

1999

Review of Progress in Quantitative Nondestructive Evaluation

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INTRODUCTIONThe automotive, aerospace, medical, and electronic industries all now use components derived from powder metallurgy. In many instances, this manufacturing approach can provide parts and stock materials of higher quality and reliability than those obtained using other manufacturing techniques, which contributes directly to the reliability of the products in which they are used. As the market for powder metal parts continues to grow, suppliers are seeking new means to monitor, control and optimize powder metallurgy processes. The focus of this work is the nondestructive evaluation of thin rolled iron aluminide alloy using thermographic techniques designed for quality control during manufacturing [1]. While the formation of products from powder metallurgy can be quite complex, the typical process can divided into four stages. In the first stage, powder metal constituents are mixed with a binder and/or solvent. In the second stage, intermediate products-commonly referred to as green parts-are formed under pressure. The third stage is the removal of the binder and sintering of the metal particles into a solid structure. A fourth stage involving machining or forming is sometimes required. Each of these stages usually has several intermediate steps and each step exhibits characteristic defect morphologies and underlying formation mechanisms. The guiding principle in minimizing the impact of these flaws (with the goal of zero defects) is to identify the most significant flaws as early in the process as possible. Early detection may provide the opportunity to correct the defect downstream in the process. Alternatively, if the flaw cannot be repaired, the defective part can be removed from the process before disrupting product flow or investing process resources in a bad part. It is in this context that the development of technologies that detect and quantify the quality of intermediate and final products will have a significant impact on the growth of future applications of powder technology. The goal of this research is a non-contact, real-time method of inspecting 100% of the green sheet produced by an existing industrial process.

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Remote measurement of in-plane diffusivity components in plates

Cited by 34 publications

References 8 publications

Determining the material parameters for the reconstruction of defects in carbon fiber reinforced polymers from data measured by flash thermography

Determining the material parameters for the reconstruction of defects in carbon fiber reinforced polymers from data measured by flash thermography

Measurement of in-plane diffusivity in non-homogeneous slabs by applying flash thermography

Thermographic Characterization of Feal Green Sheet

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