Duplicating strength of pot metal

General Composites Discussions Engineering Talk
#1

Hi, new guy here, with my second post in 5 minutes. I just found you guys. I am needing to duplicate the strength, and closely duplicate the rigidity of some automotive hinges that were originally cast from pot metal. They originally broke easily, so they were not cast very well, or engineered well, or both. My hope is, I can use a simple West System epoxy with a solid laminate of carbon, placed in 45 degree successional layers from each other.

I know this is “seat of the pants” engineering, but I would think, purely from experience that the pieces will be strong enough. These are primarily hinges on car doors, and latches that are in compression or tensile when being pulled or pushed upon, with very little static load. Most pieces are about 1/4 inch thick, 1 inch in height, and with a leverage of 2-3 inch from pivot point to end.

Any thoughts on this would be appreciated.

Thanks so much.

#2

Well of course, why not is the first thing that springs to mind! No real point in putting the fibres at 45 degrees though, you’ll mainly want uni-directional along the tensile / compressive loads (0 degrees or 90 depending on your sign convention!) You may want an outer 0/90 cloth for stability purposes in a hinge if the thing is getting slammed!
Only thing is, the pivot pin, have you some method of integrating this into your design? Generally carbon isn’t a good bearing surface and so would likely require a metal insert