The stress on the shear webbing is certainly not limited to pure shear stress in the spanwise direction, but it is also not necessarily at a 45 deg. angle. The exact nature of the stress is affected by the geometry of the structure, the relative properties of the different members, and probably some other things. My gut feel is that this situation is affected by the fact that our material is highly non-isotropic as well, but I'm getting in over my head. If I get the kids to bed early enough tonight, I may have to dig out my Mechanics of Solids book and see what I can dredge up.

banktoturn