Jun 21, 2012, 08:36 PM
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United States, OH, Bradford
Joined Jun 2005
3,440 Posts
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It's going to depend on the material, just like structures for full-scale.
If the material is equally strong in all directions, you need a structure that spreads the loads out in all directions over as much surface area as possible. Generally the outer surface has the most surface area, hence the "monocoque" or "stressed skin" structures common in all-metal aircraft.
OTOH, if the material is stronger in one direction, such as wood, or a fiber-composite material, the structure will be lighter and more efficient for a given strength if you can focus all the load paths into single directions, parallel to the max strength direction of the material. Trusses are one very effective way to accomplish this.
The problem with a truss is the miriad of joints that have to be constructed. Besides dramatically increasing the labor required, it also introduces a whole bunch of failure modes, as well as adding weight that takes away from the savings from matching the loads to the material characteristics. Like winglets, the benefits are subtle, and if you don't do a really good job on the details, you can end up negating all the benefits.
As always, the Devil is in the details.
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