Can anybody suggest me a method to calculate the weight or volume fraction in composite (carbon-epoxy)? In our work, polymer matrix composite panels were produced by vacuum molding and cured via a heating system; the resin excess is drawn out by vacuum system, so we cannot not have the weight of resin.
Bests Regards,
Amine
You can perform TGA measurements first in inert atmosphere (up to 500°C), then lower temperature (300°C) switch to oxidizing environment and rise the temperature again up to 500°C. This trick will allow to degrade the resin fraction and collect clean fibers as residue. It will provide some reliable information about composition, though it's better if you repeat the measuerement on a number of samples to get an average composition
Amine,
You could cut slices of the composite, make a thin section, and then use an image processing tool (NIH image, for example), to measure the cross-sectional fraction that is fibre (dark) versus resin (clear).
Then extrapolate the cross-sectional ratio to 3D and that ought to be good enough - assuming isotropic fibre geometry - maybe take a few slices at various angles to ensure that you get a statistically sound measure.
Thank you professor James for your attention.
Can I use image analysis software such as “ImageJ”?
Bests Regards,
Amine
You can perform TGA measurements first in inert atmosphere (up to 500°C), then lower temperature (300°C) switch to oxidizing environment and rise the temperature again up to 500°C. This trick will allow to degrade the resin fraction and collect clean fibers as residue. It will provide some reliable information about composition, though it's better if you repeat the measuerement on a number of samples to get an average composition
Thank you Laura for your advice,
It is a good idea to calculate the weight fraction.
Please, can I know if i use a standard measurement of ATG ( in terms of time)?
Cordially
Hi,
to calculat the composite constituents rate, you can take a cross section and use a imagej software to calculate the component area
further there is another method by use a formula derived from the rule of mixtures of composite density using the folowing equation:
Vf =(Rc− Rm)/(Rf− Rm)
where Vf is fiber volume fraction,
Rc is the density of the composite material,
Rm is the matrix density and
Rf is the fiber density
an attached file can help you
Regards,
Zouheyr BELOUADAH
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Provided that you have all the lab equipment, the acid digestion technique as described in ASTM is supposedly a better and more accurate technique to determine vf as it addresses issues associated with the cut/slice-then-inspect-under the microscope technique and the question of 2D vs 3D techniques. I must say it is a tedious process and needs a lot of practice to perfect the technique. I hv done both acid digestion n image analysis techniques. Good luck Amine.
Thank you dear Muhamad,
Can I have the ASTM standard which describe the acid digestion technique ?
Sincerely.
REZZOUG Amine
rule of mixtures of composite(Refer any mechanics of composite material text book) / many applications software freely available to calculate fiber volume fraction in composite
Thank you professor Srinivasa your valuable suggestions
Can I use image analysis software such as “ImageJ”?
Yours faithfully,
Amine
i think u caanot use imageJ software for calculating fiber/resin volumeratio,if it so let me know
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