Slim pressure rods such as thin piston rods may buckle outwards if the compressive force F exceeds a permissible value (Figure K 12). This value is referred to as the buckling force F K. Cylinders with a large stroke and/or a thin piston road should undergo further calculations with regard to possible buckling. Euler's formula applies in this regard to cylinders arranged vertically and to the application of centric forces.
Fluidlexikon
Buckling of rams
where l = the smallest axial planar moment of inertia
s = free buckling length (see Figure K 12)
S K = safety factor (safety in terms of buckling)
In addition to the basic scenario (scenario 1), another three buckling scenarios are possible in this context (Figure K 12). Mounting scenario 2 applies in most cases, so that s = l.
Particularly thorough calculations are required for horizontal cylinders or those tilted at a considerable angle, since the bending stress associated with the component's own weight is added to the compressive stress in such cases (Figure K 13).