flynfrog wrote:that sorta makes sense not the way I would build that part I guess.
Indeed, there are other ways for sure.
Thanks for the fantastic pictures. It's too bad the pushrod had to be sacrificed.
The laminate looks quite good, and just what you would expect for a composite structure in compression. Lots of uni plies with an occasional 45 weave to keep the uni's aligned. The laminate also has excellent consolidation with no visible voids in the highly loaded areas.
The same can't be said for the insert bond lines though. Most importantly, the machined inside surface of the composite was cut back far too much (in one picture it appears to be almost 50% of the wall thickness). While the wall of the insert has some lengthwise thickness taper, the very inboard wall should be as thin as possible (1mm or less). Having a very thin, flexible wall at the edge of a bond line helps to prevent peel failures. The voids in the bond line could also have been avoided by putting vent holes in the insert for the excess adhesive and trapped air to squeeze out.
Otherwise, it look good.
marcush. wrote:you would lay up with peel off tape to create the bonding surface ,no?
flynfrog wrote:marcush. wrote:you would lay up with peel off tape to create the bonding surface ,no?
generally peal ply makes a bad boding surface. abrading the surface gives a much higher level of surface activation and a better bond. You can also sand down to the fibers so that you bond to them instead of the resin.
flynfrog wrote:They use it as a cheap short cut in non critical areas. Peel Ply does not give you a good bond on a molecular level. Abrading will energize the atoms on they outer layer surface providing a much better bond than using peel ply. Also peel ply can leave Teflon contamination in the bond. Look up some mil specs for bonding most of the ones I know require abrasion.
xpensive wrote:what's the cross-section area of a typical pushrod like that anyway?
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