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Description, objectives

General Information

DICO (Diffusivity-Conductivity) device is an experimental setup developped par the CERTES. This device allows measuring the thermal conductivity and difusivity of low conducting materials, such as: polymers, composites, wood, gypsum, concrete, glass… This device belongs to the experimental platform PROTHERM.

Samples to characterize should have a shape of square plates of lateral extension of 44 mm and a thickness of several millimeters. Two samples can be characterized simultaneously. A view of the device is presented in Figure 1. Measurements between -20°C à +120°C can be performed (see the example of Figure 2). Measurements can also be done at various pressure levels (from 1000 down to 10-4 mbar). An improvement of the method is currently under study to allow the charcaterization of highly isotropic materials.

Measurement principle

Measurement principle is based on the use of a sinusoidal thermal excitation of the sample to characterize, bu using a thermoelectric cooler device (see Figure 3). During the experiment, the temperature of both metallic plates placed at the bottom and the top of the sample is recorded by using thermocouples. A frequency analysis of the recorded signals allows computing the experimental transfer function of the sample. Heat transfers inside the device are lodeled using the thermal quadrupoles method. Then, an inverse method allows estimating the values of the thermal conductivity and diffusivity of the sample, by performing a least-square minimization betwen both experimental and theoretical heat transfer functions.

Further knowledge

Some conference communications and articles were devoted to the description of this device:

“A simultaneous characterisation of thermal conductivity and diffusivity of polymer materials by a periodic method”, Boudenne A., Ibos L., Géhin E., Candau Y., Journal of Physics D : Applied Physics, Vol. 37 (1), pp. 132-139 (2004)

“Analysis of uncertainties on thermophysical parameters of materials obtained from a periodic method”, Boudenne A., Ibos L., Candau Y., Measurement Science and Technology, Vol. 17, pp. 1870-1876 (2006)

“Thermophysical characterization of polymers according to the temperature using periodic method”, Ibos L., Tlili R., Boudenne A., Fois M., Dujardin N., Candau Y., Polymer Testing, Vol. 66, pp. 235-243 (2018)

“Caractérisation thermophysique de matériaux polymères en utilisant un signal d’excitation pseudo-aléatoire: méthode par conduction”, Ibos L., Bodnar J-L., Candau Y., Congrès SFT, La Rochelle, 2015

“Etude de la porosité par méthode thermique”, Dujardin N., Salem T., Feuillet V., Fois M., Ibos L., Congrès annuel de la SFT 2018, Pau, 29 mai au 1er juin 2018

“Caractérisation thermophysique de matériaux polymères en fonction de la température en utilisant une méthode périodique”, Ibos L., Tlili R., Boudenne A., Fois M., Dujardin N., Candau Y., Poster présenté au congrès annuel de la SFT à Gérardmer en 2013 (poster in pdf format to download here)

Contact(s)

Laurent IBOS

DICO device booking access (restricted access to CERTES members)

Porte-échantillons DICO
Figure 1: Sample-holders of the DICO device
Conductivité thermique de polymères en fonction de la température
Figure 2 : Example of variation of the thermal conductivity of some polymers as a function of temperature
Synoptique de fonctionnement du dispositif DICO
Figure 3 : Principle of the DICO measurement method