Mechanical evaluations of structural and material composition of eggshell

Abstract

An eggshell is cracked easily by an inside load, but has strong resistance to an outside load. In this study, the structural and material composition of an eggshell (from a hen's egg) is analyzed by microscopic observation, static and dynamic penetration tests and FEM. The results obtained are as follows. (1) From microscopic observation, the eggshell is found to have a laminated structure of many material compositions. (2) The outer eggshell membrane acts as a strong adhesive agent between the inner eggshell membrane and the eggshell. (3) A cone-type punch and striker makes an initial crack easily, but subsequently large penetration energies are required. (4) The penetration energy required from outside of an eggshell is larger than from inside because it includes the energies required to break the membrane and peel it off the eggshell.