Autoclaving Carbon Fiber

[myates]

Hello,

I am having a dilemma with autoclaving some round carbon fiber handles, and I am just looking for some direction or solutions. The handle is autoclaved in an autoclavable container, with a lid sitting in such a way it is securely pressing down on one spot of the handle. After a 15 minute, 270 degree F cycle the handle will effectively dent where the lid was pressing down on it. Then after autoclaving it another time, and insuring no lid pressure is on the handle, the handle un-dented itself. What properties of the the carbon fiber would allow this to go back to its original shape after being dented or bent?

I am no expert on carbon fiber, but I a do at least know that it is made with a mesh of fibers and an epoxy. I failed in finding any specific material properties on carbon fiber. Could someone point me in the right direction to find some kind of answer to this.

Thanks,

Matt

 

[bigTomHanks]

Seems like the pressure from the lid pushed down on the plys before the epoxy was cured. After curing it stayed dented but internally it was the cured epoxy that was making it hold its shape even though the mesh was applying a pre-load from being dented. Re-heating caused the epoxy to soften up enough to allow the plys to pull the part back to the state that it wanted to be in. Provide some more details on what you are trying to figure out. If the denting was an undesired consequence then ensure the lid does not press on the part. I would also be concerned about reheating the part after curing as this may changed the structural integrity of the part overall. Posting this on the aircraft forums may get you better results as there are a lot of composite engineers in aerospace.