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Double bias fabric seems to be two plies, one at + 45 and one at - 45, stiched together, the two together can be called a 'layer' of double bias fabric. It's basically two plies of UD. See jloncomposite.com and merrittsupply.com . If this comes on a roll then I don't see why it needs...

It's usually best to take an example H/C panel and assess its performance. Use one of the usual stressing guides. Hexcel's are free and quite good ( https://www.hexcel.com/Resources/Technology-Manuals - a bit of googling will yield many more). You can calculate properties such as weight vs...

Option 2 should be most weight efficient and lowest cost too.

Usually this is done so that the inner bush on the big side can be full length, allowing the clamp-up to put the bush into compression rather than bend the forkend lugs together.

The longitudinal joint as shown appears flexible and weak. If you HAVE to break a longeron the joint should be made with extruded cleats (or maybe C-fittings) joined longitudinally by bolts. A normal longeron is continuous through a simple bulkhead and joined to it by shear cleats with at least...

You can put properties in if you know them (most test programs find adequate through-thickness stiffnesses and strengths). However, you will have a problem finding adequate failure criteria accounting for both inplane and through-thickness forces at the same time. Combinations of inplane...

Plain weave is pretty symmetric (although beware, some manufacturers use different weight plies in the 0 and 90 directions) but 5 harness or, worse, 8 harness satin weaves will curl up if cured as a single ply and should be laid up warp-side down below laminate centerline and warp-side up above...

Re Q. 2, most SMCs are short fiber reinforced rather than cloth (usually fibers are less than a mm long, but some are 'long short' fibers, several mm long) and the properties are pretty much isotropic, at least in 2 dimensions. The example you supply can be injection molded which will give a...

We don't know how detailed your model is. Are the high stresses predicted in the curved part of the corners or in some corners that are modelled more simply? A crude hand sketch would allow sensible answers. P.S.: is the FE model simple and linear static? Are the high stresses definitely...

A sketch or at least a view of the FE model with the loading and restraints will help considerably. Usually shear is helped by 45 deg plies but the fibers must be in the directions of high stress. An open-sided box will not be much good at carrying torsion. Sketch of loading and restraints...

The level of detail implies you are interested in details of the beam's behavior which will only be revealed by nonlinear analysis. If so, then yes, you need axial fastener stiffness. If you're linear-static, then no, but you also don't need such a complicated model. What are you trying to...

You could try AlBeMet, see http://www.materion.com . AlBeMet's a beryllium/aluminum alloy that's about as stiff as steel but quite a bit less dense. There are a few alloy variants. Materion are a useful reference for some fairly exotic alloys and claim to have advice for handling them. They also...

It's worth mentioning that all metals' young's moduluses divided by their densities are the same for all useful metals (and many useful composites), except beryllium (high stifness for its density), Al-lith (a tiny bit high stiffness for its density) and copper alloys (copper, brass, bronze...

If you want it lighter and stiffer than steel your options are pretty much limited to small benefits from aluminum and titanium, slightly bigger ones from an advanced aluminum-lithium alloy or larger ones from beryllium or HM or UHM continuous carbon epoxy (there are other resins but epoxy is...

Plastic filled with short carbon fibers will not be stiffer than steel and at best will typically be about as stiff as aluminum if 40% fibers are used (50% of the highest modulus short carbon fibers available (hard to get) might give a modulus of about 80 (maybe 100) GPa). Continuous high...

The carbon if woven will have a TEC of about 2e-6 / deg C if you need a little (~10%) bit of relief. Remember to add in the expansion of the Al across the panel. This is pretty rough first pass estimation. You'll need a pretty safe M.S. (I'd want at least 25%). If it's aerospace a fitting factor...

When you say 'restricted by the sandwich panel in bearing' I assume you mean restricted by the sandwich panel skins, which for some reason are not subject to the temperature change or maybe are carbon with low CTE. Are the thick 2024 plates bonded to the sandwich panel skins? If their only...

If the 2024 plates are pushing on the bolt as they expand what is restraining the bolt? A free-body diagram would help; what is pushing against what as what tries to expand? Your 'F' seems to come from the core; not possible with normal cores. Is F from the honeycomb skins? But then why would...

I'd missed the info that you're mixing some cheap 'glue' (the CMC) in the core. Maybe a little more, but you've presumably done work to try to optimise CMC content. Is cost the main driver or is weight a little bit important too? The sigma_yield strengths look a bit low to me for flax; is the...

You're presumably interested in cheap energy absorption for your eventual 'crush box'. It will help to have stuff that has a high strain to failure. It may help if it's quite weak to ensure it absorbs energy as it breaks. Your core being crushed up egg boxes may be appropriate for compression...