Design of a Carbon Fiber Composite Monocoque Chassis for a Formul.pdf

Potential Process for locating points and installing Torlon inserts:

Tldr: used a cmm to divot and mark location, drilled holes, removed core, inserted torlon insert and epoxied with a gun

1. Composite coque is complete (two halves of the female mold are joined via a lap joint)
2. Used a CMM to probe and divot the hole location (divot helps create a seat for actual drilling later)

3.a. Drilling method 1 (CNCdrill available):

• Use a CNC drill for the holes (high speed low force; ensure machine is compatible as CF dust & splinters will enter the cooling system). Part must be clamped (not overly tightened) in a fixture securely for this step.

3.b. Drilling method 2 (hand drill):

• drill must be kept perpendicular to the surface being drilled into !!!
  • To do this, a clearance hole is drilled into the face of a metal rod
  • this metal rod is then welded onto a flat plate, then use the rod as a guide and drill a hole through the plate
  • Then use this plate as a guide for drilling holes (drill through the rod basically and the rod will always be perpendicular)
  • This method would be a lot more accurate but would take slightly longer (however, since its metal it would last forever)
  • An quicker alternative method would be to just make a 3d printed version of this (petg, abs, more heat resistant). However, because it’s plastic it would wear down with repeated use making later holes less accurate

1. Drill through full sandwich panel
2. Bore out core material around hole creating a hollow donut cavity (they used an allen key placed in a drill), leaving both carbon skins intact (purpose of this step is to provide more epoxy bond area by clearing out core around hole)
3. Slide Torlon insert through hole so its flanged lips sandwich both skins
4. Inject epoxy into one port until it exits the other, cavity is now fully filled and insert is locked
5. This results in a solid reinforced load bearing hardpoint that won't crush or pull through

• Probably a good idea to reinforce critical hardpoint areas with more plies before drilling which would ensure the area is thicker and stronger
• This idea is similar to that of how potted inserts would be installed which would replace the torlon inserts