"I Beam" design

[Alik]

Originally Posted by Perm Stress

Under mast, bending load is clearly the main load. But torsions will still be here. And will try to upset any open profile beam stability.

I would use just SS strut and wire or SS tape under mast. Beam is not efficient there as it has long span and limited SM (it can't expose under bridgedeck).
Torsion will be taken by bridgedeck and cabin.

[Perm Stress]

I beam is generally suitable for materials with high shear strength and shear stiffness. It generally mean metal. I did not hear much about I beams made of composites...

[Alik]

Originally Posted by Perm Stress

I beam is generally suitable for materials with high shear strength and shear stiffness. It generally mean metal. I did not hear much about I beams made of composites...

Yes, there are some T-bars in composites, not I-beams. For composites, better use square pipe or top hat sections that makes it easy to produce leaving no open edges.

[Perm Stress]

Originally Posted by Alik

I would use just SS strut and wire or SS tape under mast. Beam is not efficient there as it has long span and limited SM (it can't expose under bridgedeck).
Torsion will be taken by bridgedeck and cabin.

My guess if beam is used, it would be embedded in bridgedeck structure; than bridgedeck would take care for stability/buckling) of beam, among its other functions.

If structure in its entirety is made from materials/members with significantly different stiffness/strength (glass/carbon for example) properties, FEA would be in order, to eliminate uncertainties on interaction.

[Alik]

Originally Posted by Perm Stress

My guess if beam is used, it would be embedded in bridgedeck structure; than bridgedeck would take care for stability/buckling) of beam, among its other functions.

It is exactly what we have done, but we used top hat section between bridgdeck plating and cockpit deck. Still flexible.

[brian eiland]

You might have a look over here...one of the smaller racing cats on that Swiss lake that was the predecessor to the Alinghi America's Cup catamaran

...lots of creative support rigging ...underneath

Sail Loading on Rig, Rig Loading on Vessel

How fast can Alinghi's huge cat be?

[Alik]

Originally Posted by brian eiland

You might have a look over here...
...

Thanks, interesting reading.