The cylinder has to strong enough to withstand high gas pressure , thermal stresses due to heat transfer through the cylinder wall, hard enough to resist wear due to piston movement, and it should be corrosion resistant. Cylinders are made of grey cast iron which is centrifugally casted. For heavy duty cylinder , nickel cast iron and nickel chromium cast iron are used. In some case cast steel and aluminium alloys are used. there are two principle stresses in engine cylinder wall, the circumferential hoop stress and longitudinal stress and by considering FOS, Biaxial stress at any point in cylinder wall we have to design BORE size, Length, Thickness of the cylinder.