How to do the structural analysis of a simple composite structure??

[rcairplanenut]

Hello every one

What would be your best recommendation for the structural analysis of a rectangular plan form wing using polyurethane foam with e glass on each side for the skins and ribs with a Kevlar and S-glass I beam spar. The fuse uses the same polyurethane foam and e glass skins with Kevlar and S-glass longerons.

The I beam spar supports most of the bending however the skins will take some of that how will that be considered in the analysis??

Also How is the Torsion and shear considered in the structural analysis of a composite structure??

Would you use M*c / I ?
V*Q / I*T ??
shear flow calculations?
Matrix Methods?
Will Hooks law ( stress / strain = E ) still apply to the Kevlar and S-glass spar??

Does anyone know the structural analysis methods that Burt Rutan used on the Long eze exc, that information might help me?

Most of my Aeronautical Engineering background at Embry Riddle was focused on metallic structures. However I am the most proficient in laying up glass and foam composite structures. Any recommendations on text/reference books and methods would be of great help.

Thank you

SG

 

[polymire]

For simple calculations of composite structures,
there is nothing 'magical' about composite materials, they have a thickness and a stiffness. One of the problems is that the stiffness changes with direction (depending on the cosnstruction of the composite).
So this question can be translated into
"what are the material properties for my materials ?"

well I can have a go at estimatint the material properties, provided you supply a lot more detail about the construction of the composite.

the e-glass composite...is it composed of unidirection glass fiber, chopped glass fiber.
what are the angles of the fibers ?

for the foam...what is the approximate density (the stiffness of the foam changes with density).