Fixing a seat support that cracked (shattered?) in a crash
First, the shattered design, in place:
Taken off the bike it's easier to see the break, which is surprisingly uneven for the top layers. I would have expected a more clean break here.
Taking a closer look at the bottom piece, the metal rods essentially just punched through the bottom bracket in the rear of the design.
Taking a look at the underside, we can see that the rods essentially ripped out the infill and bottom layers, leaving the shell walls. My initial intuition is that this suggests that we can make the overall design stronger with more shells, but I'm curious to think through if that would transfer stress to other portions, or perhaps the limitation in strength is the bonding between the bottom layers and the walls.
Here's a better look at how the top shattered. Overall, it's harder to see a consistent trend in how it broke, but looking near the inner ring and outer surfaces, it does seem to be more continuous and less varied for the outer shells.
It took resurrecting some older design files, with some updates (that so far seem to be improvements). The bottom has a bit of a wider ring for easier printing and there are more shells internally. Time will tell how this design holds up, although it's largely waiting for another crash before we'll really get a test.