From bifurcation to snap-through buckling of elastic thin shells for soft robotic materials

Elastic thin shells are well-known for their highly unstable post-buckling response that exhausts their pressure bearing capacity and leads to catastrophic collapse. This paper examines elastic thin shells with a large axisymmetric imperfection that can escape the classical bifurcation of perfect spherical shells. The results show that the imperfect shell undergoes snap-through buckling followed by a stable post-buckling that offers increasing resistance to pressure over a large shell deformation. In addition, a sensitivity analysis on the role of defect geometry reveals the emergence of four buckling modes. The findings show that harnessing defect geometry can be effective in programming the post-buckling characteristics and transition between buckling modes, thus offering potential routes for the design of soft metamaterials.