nnop
Marine/Ocean
- Oct 18, 2005
- 1
Hello,
I have been trying to calculate the maximum pressure a carbon fiber composite tube will handle with out much luck, maybe someone here could help.
The basic parameters are:
standard modulus carbon fibre, 300 gram per square meter, 0.3mm thick per layer, 2 layers of hoop (ie 90 degrees to the longitudinal axis) 2 layers longitudinally. Fibre is approx 2400MPa tensile strength including the epoxy resin within the fibre.
Tube dimensions, 1.5" inside diameter. Length unknown but assuming infinite length or infinitely strong end caps. i.e. failure mode will be through the side of the cylinder.
At what internal pressure will the tube rupture?
I have used a formula in an engineering handbook that is applied to metals. Using the above data in that formula gives me an answer of 13,151 psi which to me, based on experience, is far to high. The formula given was
t=p.D/2.S
where t is the wall thickness in mm, D is the inside diameter in mm, p is the pressure in MPa (or N/mm^2), S is the maximum allowable tensile stress in N/mm^2.
A little about me: I work for a company in New Zealand that specializes in custom made carbon composite tubing. We supply mainly marine industry but often get odd requests and unusual applications other than structural for our products. The above was brought about from a guy who wants to make a water rocket altitude record. It would be nice to be able to answer his question of how much pressure our tube will handle but this problem is beyond my understanding of engineering in this field.
Regards,
Neil Waterhouse
I have been trying to calculate the maximum pressure a carbon fiber composite tube will handle with out much luck, maybe someone here could help.
The basic parameters are:
standard modulus carbon fibre, 300 gram per square meter, 0.3mm thick per layer, 2 layers of hoop (ie 90 degrees to the longitudinal axis) 2 layers longitudinally. Fibre is approx 2400MPa tensile strength including the epoxy resin within the fibre.
Tube dimensions, 1.5" inside diameter. Length unknown but assuming infinite length or infinitely strong end caps. i.e. failure mode will be through the side of the cylinder.
At what internal pressure will the tube rupture?
I have used a formula in an engineering handbook that is applied to metals. Using the above data in that formula gives me an answer of 13,151 psi which to me, based on experience, is far to high. The formula given was
t=p.D/2.S
where t is the wall thickness in mm, D is the inside diameter in mm, p is the pressure in MPa (or N/mm^2), S is the maximum allowable tensile stress in N/mm^2.
A little about me: I work for a company in New Zealand that specializes in custom made carbon composite tubing. We supply mainly marine industry but often get odd requests and unusual applications other than structural for our products. The above was brought about from a guy who wants to make a water rocket altitude record. It would be nice to be able to answer his question of how much pressure our tube will handle but this problem is beyond my understanding of engineering in this field.
Regards,
Neil Waterhouse