composite panel inserts

[CatiaDesigner]

I am looking for info on double countersunk inserts with thru holes for fully composite panels (nomex honeycomb and carbon fiber laminate) that ideally could be co-cured in position.

application is for nacelle cowl doors to hold on hinge and latch fittings that will improve/prevent fasteners pull thru during fire tests.

anyone have experience with such a beast?

 

[EVdave13]

catiadesigner: I know of no double-countersunk insert. You might try machining a countersink into the opposite side of a countersunk NAS1834. Also, you might look at some of the two piece inserts that are available from companies like TYE (the young engineers). I think they can mix and match insert halves to a slight degree, and they may be able to get a countersink on both sides. The down side is that they are designed to grip the panel between the insert flanges, and so are usually used on metal panels. Good strength, though.

For co-curing, just select a potting compound that can withstand your panel cure cycle, and prepot the inserts during layup. A slow curing one is best, so that they can still adjust things a bit during final layup, before it goes in the autoclave.