Energy absorption of composite 3D-printed fish scale inspired protective structures subjected to low-velocity impact

This paper reports the performance of protective structure inspired by elasmoid fish scales, employing a combination of experimental and numerical techniques. The composite scale-tissue structures were fabricated using a 3D printer with a dual-material extruder. Each structure was subjected to low-velocity impact using a drop-weight tower system. Investigation of the progressive failure mechanisms relied on finite element analysis and high-speed photography. Geometrical parameters of fish scales, including scale volume fraction, scale overlapping angle, and radius of curved scales were studied for their influence on impact resistance. Further, using Taguchi's method for the design of experiments, it was determined that enhancing impact resistance was achievable through an increase in scale volume fraction (by 15.1 %) and a larger scale overlapping ratio (by 39.4 %). The outcomes suggest that using a composite scale-tissue structure can contribute to developing more effective protective structures.