composites: contained in volume weight

[Dmaz]

Hi, it's definitely a trivial problem, but I don't come out of it. .
I have to find the density of a carbon-epoxy laminate having available:
the weight content of the resin equal to 42%
carbon density: 1.77
the density of epoxy resin: 1.2

I have always used the "rule of mixture" but I must have the content in volume for this formula while now I have the content in weight. .
Thanks to who will help me!

 

[zeigs]

I would say
1.77*(1-42)+1.2*.42=1.53

Hi.

 

[Dmaz]

this is the rule that I used when I was wrong. .
with this formula you have to use the content in volume while I have the content in weight...

 

[zeigs]

You're right, I'm asking for vein. I'd be wrong, too. the right formula is

1/(.42/1.2+(1-42)/1.77)=1.475

to counterprove the calculation of the percentage in volume is the solution of the equation

1.2*x/(1.77(1-x)+1.2x)=42

that from a percentage in volume of .516 that put in the formula of the previous post from again 1.475

see to claim to reason before having taken coffee?:tongue:

 

[Dmaz]

Thank you very much!!! I found the same result this morning.
They're the simple ones that sometimes send you to mental blackout! :tongue:
Thank you again! :smile: