Determine Young's Modulus and Shear Modulus of Woven Roving 1

[fglass]

Question: If the fiber weight per unit area of a woven roving(WR) is given as 24oz/sq yard fabric with a 5 X 4 weave style, is it a wise idea to calculate the Young's Modulus (Tensile Modulus) of the WR by assuming different volume fractions (Vf=0.3,0.4,0.5,0.6 etc)?
From what I understand,

Vf=W/(t*d)
where, W=weight per unit area (known value)
t=thickness (known value)
d=fiber density (known value)

I saw this equation from a book. Is this equation make any sense to everybody? Besides that, I wonder if anybody know the way to calculate Young's Modulus, or Shear Modulus, of WR, Chopped Strand Mat, Continuous Filament Mat and Roving if testing is unapproachable at this point?

Your help is much appreciated.

 

[Blackhorse007]

wat is the fiber used for?

well i think that if the formula is ok, that is what the chinese design institutes are doing. but it still depends on the application.

 

[fglass]

I am helping my boss to set up a material library for future laminate analysis used. He wants me to determine the properties of 24oz/sq yard fabric WR at different volume fractions (Vf). Referring to the equation above, it would end up with only one Vf value since W,t,and d are known.

To reduce the cost of testing, I need to give a wise guess on the Young's Modulus, Shear Modulus and poisson ratio of each materials (WR,Chopped Strand Mat,Continuous Filament Mat,Roving). I contacted the supplier but they couldn't provide me those data. Therefore, I am wondering if anybody has any ideas to calculate those properties? Thanks.

 

[Peter]

Look in CE 12215-5. They have a method for calculating strength and stiffness for a given volume fraction. It is not exact, but it is very close.

 

[Oceania]

There is some public domain data published for tensile strength and modulus vs fibre volume fraction, some resin manufacturers have data for general laminates ie. all CSM or WR/CSM. Most good books on composite materials will have the data and hopefully should give resin type, manufacturing process and glass type. However unless the data comes from a very trusted source then it should be seen as indicative. Calculating properties is fine but you need to balance this with the manufacturing process so you know what levels of Vf are achievable. JA Quinn published a book "Composites - Design Manual" which contains a lot of this "typical" information and is good as a starting point

http://www.iom3.org/consult/quinnassoc.htm

(I am only supplying this web address for info only) Of course there are other publications that may also include this information.