Influence of deformations before instability on the parametric instability of conical shells under periodic pressure

On the basis of the dynamic version of linear Donnell type equations and with deformations before instability taken into account, the dynamic instability of clamped, truncated conical shells under periodic pressure is analyzed. The principal instability regions are determined by combining Bolotin's method and a finite difference procedure. Calculations are carried out for two kinds of conical shell. The effect of bending deformations before instability is found to change the width of the principal instability regions in the vicinities of twice the natural frequencies of asymmetric vibration. Other principal instability regions are detected in the neighborhoods of the resonances of symmetrically forced vibrations.