Dynamic Buckling of Inelastic Spherical Shells

The dynamic buckling behavior of a complete spherical shell made of a bilinear or work-hardening material and under a uniform external impulsive loading is investigated. A quasi-bifurcation theory and a minimum principle are employed to determine, respectively, the onset of the dynamic buckling process and the post-bifurcation nonlinear behavior. Numerical results are obtained for a number of elastic and elastic-plastic cases. The results indicate there is a softening effect in the plastic deviated stress-strain relationship which makes the spherical shell less stable. Furthermore, the higher order terms in stress and strain measures and the coupling of symmetric and asymmetric modes of motion cannot be neglected in the post-bifurcation analysis.