Creep response of polymeric honeycombs

Creep response of polymeric honeycombs

It is relatively easier to measure experimentally viscoelastic properties of a material. However, when a hollow profile/structure is made of this material, it is not straightforward to predict the viscoelastic response of the cellular structure at the bulk level. This is because of the fact that the cellular material has two different length scales: one at the bulk level and another at the cell level, and hence, the cell level properties significantly affect the bulk behaviour. The aim of this study is to predict the stress relaxation characteristics of the cellular material at the macroscopic level in terms of the stress relaxation characteristics of the cell wall material i.e. at the cell level, topology and cell size. The primary interest is to investigate the out-of-plane viscoelastic properties of the core material. This is because when a sandwich panel is subjected to bending, the core carries primarily the major shear loading in its out-of-plane, whereas the skins carry the major flexural load. Honeycomb made of hexagons (of equal sides) is chosen as topology as it is the most common topology among the cellular cores.