Talk Composites - The Forum for Advanced Composites

Breaking strength calculation of a sailboat bowsprit needed

http://www.talkcomposites.com/Topic31567.aspx

By carbon-charly - 1/8/2019 4:20:34 PM

Hello everyone,

I'm new in the forum, and already have my first question :-)

Who is able to do me a non-binding rough breaking-strength calculation for following sailing-boat-part made of carbon? Example pic at the end of this text.

It is about a so-called BOWSPRIT pipe (for the gennaker sails).

I'd like to change my old aluminum one for a carbon one.

My old aluminum tube has 8.5kg incl all fittings. The carbon tube only 2.5kg.
I haven't used it yet. I would like to ask forum experts first.

Conclusio should be: Is the carbon tube sufficiently dimensioned or at least as stable as the one made out of aluminium?

I have following info for you:

old aluminium tube:
- alloy: probably AlMgSi0,5
- Length: 2,300mm (approx. 1 meter boom, the rest is screwed on deck with 2 clamps)
- outer diameter: 80mm
- Inside diameter: 72mm
- Wall thickness thus: 4mm
- Weight of the pipe without fittings approx. 8 kg

Carbon tube:
pullwinded
- Length: 2,300mm (approx. 1 meter boom, the rest is screwed on deck with 2 clamps)
- outer diameter: 80mm
- Inside diameter: 76mm
- Wall thickness thus: 2mm

fiber alignment: Unidirectional inside + 75°/35° outside
fiber volume: aprox. 60 %
surface: smooth, shiny
temperature resistance: up to 110 °C
tensile-E-Modul: 240.000 MPa
tensile strength: 4.000 MPa
fracture strain: 1,50%
density: 1,8/cm³
thermal expansion coefficient: -0,1 * 10-6*K-1 along the fiber
radiolucent: 100%
specific elctrical resistance: 1,6*10-3Ohm*cm
heat conductivity: 17 [W/(m*K)]
specific heat capacity: 710 [J/kg*K)]
no vibrations
UV-resistent by using standard varnish
corrosion-resistent: e.g. petrol, oil, saltwater, hydrofluoric acid
handling: drill, mill, cutt, glue 

weight: approx. 1kg per meter

Would be super nice of you if you could help me

Many thanks in advance


By oekmont - 1/12/2019 6:37:12 AM

No.

Oek (Ök) is what my closest friends call me.
Mont is just an internet affix to make it sound a little French (which I am not).