Thermophysical Laboratory BABOU Amine EADS CRC France SERVICE DCR/MP/MC Thermophysical Laboratory Thermal characterisation of an UD carbon fibre / epoxy composite Methods of characterisation -Thermal conductivity direct measurement in plane X, Y « hot guarded plates » -Thermal diffusivity through thickness « Flash » -Thermal capacity « D.S.C. » -Thermal diffusivity in plane X,Y « Thermography » Results

F With F = U * I = FT + FL FT = Transmitted flow FL = Lost flow e = sample thickness ( 5 to 28mm ) S = sample section ( 25mm diameter ) T1 Tc Sample Thermic well F U, I Cold plate T2 Th Hot plate l = U * I * e / S* [(T12-T22) + [(T11-T21)] CONDUCTIVITY « Hot garded plates » METHOD The method consists in measuring the necessary heat flow ( F ) to maintain one difference of temperature about 10°C between the two faces of the test specimen. First condition « adiabatic » Th = Tc FL = l * S * ( T11-T21 ) / e Second condition Th = Tc + 10°C F = U * I = l * S * (T12-T22) / e Conductivity determination with:

TEST SPECIMEN PREPARATION FOR IN PLANE CONDUCTIVITY MEASUREMENT F=25mm, h=28mm Cube of 30*30*30 mm3 Obtained by sticking Direction of measurement Composite panel X Y

between the measured signal and the calculated signal. DIFFUSIVITY 1D ALONG Z « Flash » METHOD The method consists in imposing a dirac of energy on a face of the test specimen and to measure on the other face the temporal distribution of the temperature. Thermal diffusivity is determined with a thermal model by making the comparison between the measured signal and the calculated signal. Lens Infrared detector Laser 90j/ 350ms Sample Diffusivity calculation Losses thermic flow calculation 0,1 0,2 0,3 0,4 0,5 0,6 0,7 0,8 5 10 15 20 25 30 35 t (s) T red Increasing expérimental thermogram 0,2 0,4 0,6 0,8 1 1,2 10 20 30 40 50 60 70 t (s) T red Decreasing expérimental thermogram

Expérimental thermogram Calculated thermogram instataneus diffusivity

CAPACITY «Differential Scannig Calorimeter » METHOD The method consists in measuring the difference of heat flow ( DW ) to maintain the sample in the same conditions as the reference. - Référence Sample DW T(°C) D. S. C. CpS = ( DW / V* mS) + ( mS x Cpr / mr) With V = dT / dt temperature kinetics mS = sample weight mr = reference weight Cpr = reference capacity

DIFFUSIVITY ALONG X AND Y 2D « Flash » METHOD The method consists in imposing a dirac of energy in the center of a face of the test specimen and to measure at any time on the other face the spatial distribution of the temperature. Thermal diffusivity is determined with a 2D thermial model. Laser 90j / 350 ms IR Camera X Y Sample

( ) Fourier transformation ² , ln t a - ÷ ø ö ç è æ = q Picture at t1 Picture at t2 Average along Y axis at t1 Average along Y axis at t2 X Y T Fourier transformation ) ( 1 2 ² , ln t a x - ÷ ø ö ç è æ = q ax identification

TECHNICAL SPECIFICATION OF EQUIPMENTS

MATRIXES OF RESULTS Calcul. l = « a » * « r » * « Cp »