An investigation on the mechanical behaviour of sandwich composite structures with circular honeycomb bamboo core

Abstract

Sandwich panels made with a bamboo core of different dimensions, packing geometries and facing materials are subjected to three-point bending tests and assessed through statistical and failure analysis. In addition to promoting a circular economy, this architecture holds great promise for replacing secondary structural components in sustainable construction and transportation facilities. The statistical analysis responses are associated with the equivalent density of the panels, flexural strength and modulus of the panels, skin stress and core shear strength and modulus. Individual bamboo rings are also characterised using physic mechanical and interfacial bonding tests. Treated aluminium face sheets provide the best mechanical performance compared to glass fibre-reinforced composite (GFRP) ones by increasing the overall properties of the sandwich panels. The specific face sheet material and void percentage affect the equivalent density, with lower values (~ 0.48 g/cm3) when using GFRP skins, larger bamboo rings and cubic packing. Sandwich panels with 30 mm bamboo rings and hexagonal packing provide higher flexural properties, i.e. ~ 43 MPa strength and ~ 7.6 GPa modulus, and skin stress (~ 288 MPa), while those with 20 mm bamboo rings have higher shear stiffness (~ 132 MPa) and resistance (~ 3.33 MPa). Sandwich panels made with aluminium skins show evident skin-polymer debonding, while those with GFRP have premature skin failure and lower structural performance. The proposed sandwich panels present remarkable and competitive mechanical performance concerning commercial analogous structures, generally used in the aeronautical and automotive industries.