Mechanical performance of riveted Al-sandwich composites with functionalized bio-cores

Abstract

In this study, a sustainable sandwich composite was created and tested for mechanical efficiency. The composite is a structurally modified ground wheat straw reinforced polyester core laminated between two aluminum faces connected with rivets. In order to unify the two materials, different percentages of 3-aminopropyltriethoxysilane were added to the polyester to promote cohesive compatibility between the hydrophilic filler and the hydrophobic polymer matrix. Rivets also provided a strong mechanical bond for the load paths between the core material and the aluminum shells, creating an interface for efficient load transfer. The mechanical properties of the materials were evaluated using both three-point bending and impact tests. The flexural strain of 0 wt% KH550 increased from 2.8 to 7.4% with 9 wt% KH550. This is an approximate increase of 164% overall. The increase in flexibility has resulted in a decrease in flexural strength from 130.1 to 104.1 MPa; however, impact resistance of the material has greatly increased. Core impact strength increased from 3.04 to 7.75 kJ/m², and the combined total of the core and aluminum faces increased from 27.2 to 43.5 kJ/m².

Graphical Abstract