cpinz,
I'll be sure to get my calculations revised by an expert. I'm trying to get in touch with people that already designed aircraft with carbon spars here in Brazil, by now just trying to learn and do most of calculations i can in ways of getting a starting point for dimensions.
Also, i'll...
UD fibers can be used, no problem at all. But wasn't it noted before that could be issues eith manufacturing on homebuilts with UD?
Also, 70GPa is for the laminated of the CF.
Since i modelled my beam with different materials and i'm able to obtain the normal and shear stresses on my spar...
Yes, using CF just like this image, some fibers will be aligned and some will be at 90°
The beam neutral line is in the middle of the spar, and stresses are symmetrical on the top and bottom of the beam. The stresses are different on the two "layers" of CF on each spar cap (upper and lower)...
cpinz,
About what would be the limit load, i plan on using 150% on the loads and 150% to 200% on the material for Ultimate stress calculations.
The properties i got for standard CF are:
Young Modulus on the fiber direction: 70GPa
Young Modulus on loading at 45° with fibers: 17GPa...
tbuelna,
This is my first composite design, so being conservative is sure a must, and ill be sure to account for those building concerns, Thanks!
cpinz,
I'll take a nice read at those rules.
I'm sorry, but i suppose L.L. and U.L. you mean Lower layer and Upper layer, right?
I'ill be sticking...
This is for a homebuilt im planning on, still on the preliminary design by now, and this is my first composite spar design.
SWComposites,
Actually considering only the core i could find a Divinycell that can support the stresses, but after a analysis and comparing with 45° fibers on the web, i...
Having fibers in 45° on the web was my first idea, so shear stresses would become only normal stresses to the fiber, but wouldn't it be a problem on the web section close to the edges, where the normal stresses due to bending moment will apply forces 45° to the fiber direction?
Could you give...
Hello to all!
This is my first post here.
Im designing a main wing spar where a Divinycell rectangular core will be laminated with 90 degrees carbon fiber on the four sides, to make a home building easier and possible.
In order to do so, I started with a analytical beam model that supports the...
