Static and kinetic limit loads of spherical shells

Imperfections,or more general perturbations, of shells may be of different type regarding the geometry, boundary conditions, material parameters and loading. Perturbations may be classified into initial and non-initial ones to emphasise the time or the load level when a kinetic or static perturbation occurs in a system. Winterstetter & Schmidt (2002) classify initial geometrical perturbations into realistic, worst and stimulating perturbations, whereas stimulating ones may be interpreted as unfavourable perturbations.