Damage behavior and dynamic response of nano-silica reinforced aluminum 2024-T3/GFRP composite laminate subjected to high-velocity impact

This study focuses on analyzing the damages and ballistic limit for the fiber metal laminate (FML) and nano-silica reinforced FML. FML materials are hybrid sandwich composite materials used in lightweight structural applications. FML is constructed as a sandwich structure by bonding an aluminum alloy and a glass fiber reinforced composite. To enhance the impact strength of the FML composite, it was reinforced with nano-silica particles within the epoxy resin at various concentrations ranging from 1 wt% to 7 wt%. The laminates are then subjected to high-velocity impact tests using a single-stage gas gun setup, to assess the failure modes of the FML in an aluminum sheet and nanocomposite layers. The influence of nano-silica on natural frequency and damping factor is also examined by using a shock sensor and DAQ (Data Acquisition system). Results indicate that the FML laminate containing 5 wt% nano-silica demonstrates superior impact resistance compared to other filler percentages, as demonstrated by the ballistic limit and damage assessment. The ballistic limit for the pure FML laminate without nano-silica is 98 m/s, whereas the FML laminate containing 5 wt% nano-silica exhibits a peak value of 112 m/s, presenting a notable 14.3% increase in ballistic limit compared to the pure FML. Additionally, the dynamic response analysis reveals changes in the natural frequency values of the laminates before and after impact, indicating permanent damage to the laminate structure.