Improving the interlaminar shear performance of hybrid nano‐filled <scp>3D</scp> woven composites using response surface methodology

Abstract The present work aims to improve the interlaminar shear performance of three‐dimensional orthogonal woven E‐glass/epoxy composites (3DOWCs). The epoxy resin was modified with different weight percentages of hybrid nano‐fillers that is, acrylic tri‐BCP M53 (Nanostrength® [NS]: up to 7.5 wt%) and graphene nanoplatelets (GNP: up to 1.5 wt%). A response surface methodology (RSM) based on central composite design (CCD) was used to optimize the input variables for maximum interlaminar shear strength (ILSS) in the warp and weft directions. Experimental results showed that the ILSS of 3DOWCs increased by 22.7% (warp) and 23.4% (weft), when reinforced with 2.5 wt% NS: 0.5 wt% GNP and 5.0 wt% NS: 1.7 wt% GNP, respectively. Scanning electron microscopy of damaged samples indicated that GNP‐induced crack pinning, coupled with NS plasticization and fibril formation, contributed to improved interlaminar damage resistance of 3DOWCs. Furthermore, the optimal formulation with p &lt; 0.05 &lt; F of 3.91 wt% NS and 0.5 wt% GNP led to an increase in ILSS of 18.5% and 16.5% along the warp and weft directions, respectively. The findings of this research demonstrate that low concentration of hybrid nano‐fillers can effectively reduce the damage severity in 3DOWCs under shear loading. Highlights The addition of hybrid nanofillers improved ILSS by up to 23%. Hybrid nanofillers reduced the damage severity in 3DOWCs compared to pristine 3DOWCs. Crack pinning/bridging by GNP and NS plasticization enhanced interlaminar damage. Interlaminar shear performance was optimized using the CCD‐based RSM method. 3.91 wt% NS and 0.5 wt% GNP give maximum ILSS performance of 3DOWCs.