Stability of a spherical cap loaded by the external pressure

The stability phenomenon of elastic, spherical shells is examined numerically by the finite element methods. The attention is focussed on spherical caps clamped along periphery and pressurised externally. The stability phenomenon depends on the cap rise. Very shallow shells do not exhibit instability symptoms. Shells of higher rise exhibit typical snap-through buckling. When the rise is greater the bifurcation phenomenon appears as well. The spherical shell of the particular rise is analysed in details in the paper. The fundamental path and all bifurcation paths splitting from the fundamental one are calculated. Secondary bifurcations are registered in this particular case as well. The most desired forms of geometrical imperfections are indicated. The ‘worst’ imperfections are determined as well.