Numerical investigation of Fibonacci series based bio-inspired laminates under impact loading

The present paper addresses the development of bio-inspired composite laminates based on the Fibonacci sequence for impact resistant applications. Four methods such as thickness ratio (FT), incremental angle (FI), hybrid (FY) and Fibonacci helicoidal (FH) are devised to create various sets of laminates to exploit the Fibonacci sequence into the laminate design. These methods include controlling of ply group thickness (FT), rotation fiber angle (FI), both thickness and angle (FY), and direct implementation of Fibonacci based helicoidal laminate sequence (FH). The performance of these proposed laminates is analysed by considering ballistic impact loading with six different impact velocities, out of which three are below the ballistic limit of laminates. The behaviour of these laminates under this loading is investigated using an elastic-plastic progressive damage based numerical model. The results obtained through numerical simulation are validated with experimental results and found to be well correlated. The performance of bio-inspired laminates is compared with conventional cross-ply and quasi-isotropic laminates in terms of various parameters such as residual velocity, displacement, energy absorption, peak load, number of plies damaged and delamination. These parameters are correlated by using a level-based methodology and the most versatile method to design Fibonacci based bio-inspired laminates among all methods considered is estimated for all velocities.