The Influence of Fiber Stacking Sequence on the Mechanical and Impact Performance of Sustainable Epoxy/Basalt/Aramid‐Balsa Sandwich Composites

ABSTRACT This study investigates the mechanical and impact properties of a novel class of eco‐friendly sandwich composites, combining basalt and aramid fibers with an end‐grain balsa wood core, using an epoxy polymer (MGS LR160/LH260S) as the epoxy matrix. The research focuses specifically on the critical role of fiber stacking sequence within the composite skins. Four configurations were fabricated and tested according to relevant ASTM standards. The results demonstrate that mechanical performance is highly dependent on layup stacking sequence. The Basalt/Balsa configuration achieved superior flexural properties (75 MPa strength, 80 GPa modulus), while the Aramid/Balsa configuration exhibited optimal impact resistance, absorbing 96% of the impact energy (24 J) through progressive failure mechanisms. The hybrid AB‐Balsa design showed enhanced tensile performance, achieving a strength of 17.5 MPa, which was 13% and 23% higher than the monolithic Basalt/Balsa and Aramid/Balsa configurations, respectively, underscoring the benefit of placing ductile aramid fibers in the outer layers. Conversely, the BA‐Balsa hybrid suffered from premature failure due to interfacial delamination. The balsa core universally improved damage tolerance. These findings provide critical design guidelines for lightweight structural applications requiring a blend of strength and impact resistance, such as electric vehicle battery shields, marine hulls, and protective paneling.