Mechanical Behaviour of Sustainable Sandwich Structures
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The combination of lightweight properties and high energy absorption capacity makes sandwich structures suitable for applications in transportation industry, such as automotive, aerospace, and shipbuilding industry. Moreover, in these fields, the gas emissions reduction, fuel saving, vehicle safety and load capacity increase are currently important requirements. This study deals with the study of the mechanical behaviour of a hybrid green honeycomb sandwich structure made by an aluminium honeycomb sandwich panel reinforced by flax fibres reinforced skins. The aim of this research is to evaluate the mechanical properties of these hybrid sandwich structures, by analysing their bending behaviour and low-velocity impact response. For the impact tests, an indenter having hemispherical geometry with a diameter of 20 mm (H20) was selected. The results were compared with other hybrid structures analysed in previous studies. The static three-point bending tests produced different collapse modes, depending on the support span distance. Non-destructive evaluation, by optical microscopy and radiography (RT) was carried out for failure mode and damage analysis. In the aluminium-flax hybrid sandwich structures it is found an increase in the impact strength of 38% compared to unreinforced aluminium honeycomb sandwich structures. In terms of specific energy absorption (SEA), it is interesting to underline an increase of 14% compared to traditional AHS structures. This investigation has particular importance for applications that require lightweight composite structures with high energy absorption capacity as in transportation industry, where crash and collision phenomenon have increased year by year.