We attempted to model static stresses from mounting the cylinder head, thermal stresses, and mechanical stresses from mass forces, combustion forces and the like.
Our goal was to achieve low combustion gas blow-by, low oil ingress into the combustion chamber, yet low friction between piston and cylinder wall.
We used simulations (about three months worth IIRC) and measurements to generate data points for a continuous ersatz model of the physical phenomena, then performed multi-criteria optimisation on that model. The resulting shape was interesting, but not exactly earth-shattering. Kinda randomly warped.
This work was tremendous fun, and I learned a lot.
If anyone is interested (and can read German), it resulted in this dissertation: https://books.google.de/books/about/Tribo_System_Kolbengrupp...