Optimal barreling of steel shells via simulated annealing algorithm

The load carrying capacity, of externally pressurised and optimally shaped metallic shell, has been increased by 40% over the performance of an equivalent cylinder. The optimal geometry has been sought within a class of generalised ellipses by the application of simulated annealing algorithm. The optimal solution has been verified experimentally by collapsing two, nominally identical, CNC-machined, mild steel shells at about 17 MPa. The wall thickness of the optimal shell was about 2.6 mm, its height was about 100 mm and its diameter was 200 mm. The effect of initial geometric imperfections on the ultimate load is also discussed. The comparison of theoretical and experimental results is good.