Low velocity impact response of fiber metal laminates with nano-patterned metal surfaces  

A nano-scale electrochemical sculpture (NES) method has been developed to enhance the bonding strength of fiber metal laminates (denoted as FMLs-NES). The influence of NES surface treatments on the low velocity impact response and static mechanical behavior of FMLs was systematically investigated and compared with traditional surface treatments such as mechanical polishing and NaTESi anodizing (denoted respectively as FMLs-PS and FMLs-NaTESi). The examination of the damage area and energy absorption under different impact energy levels revealed that the FMLs-NES specimen exhibited the smallest damage area and energy absorption while maintaining the structural integrity after impact. Finite element simulations were conducted to inform the impact damage progression and failure mechanisms, the results indicate that the interfacial failure mainly occurred between the middle titanium sheet and the bottom 90° fiber layer and propagated from the long edge to the center of FMLs. The experimentally validated finite element model can also be employed to optimize the stacking sequence of FMLs and to predict the residual strength after impact, where the FMLs-NES showed the highest residual strength.