Buckling of longan-shaped shells under external pressure

This paper carries out an experimental and numerical study on the buckling behavior of a biologically evolving longan-shaped shell under external pressure. Such a shape, following Cassini oval formula, is determined based on the measurements of 171 actual dried longan shells. On this basis, three nominally identical longan-shaped shells with the shape index of 0.11 are fabricated using stamping and welding process, measured for geometry, slowly tested to destruction, and numerically evaluated for their buckling behaviour. A good agreement between experiments and numerical evaluations is obtained.