Low-Velocity Impact Response And Experimental Optimization Of Modified Fiber Metal Laminates With Integrated Mechanical Interlock Bonding System

This paper presents a modified version of fiber metal laminates with integrated mechanical interlock bonding system for aerospace applications. Sheet metals of Al 2024-T3 with surface machined infinitesimal hooks are used along with impregnated glass fiber composites to manufacture a modified version of GLAss REinforced aluminum (GLARE). Low-velocity impact responses of the modified GLARE is examined using a drop weight impact testing machine at an impact energy of 7.5 J. To optimize the geometry of the machined hooks to maximize the modified GLARE low-velocity impact resistance, we developed and tested four configurations of modified GLARE with four variants of hooks’ geometry, including two hook sizes, namely, nano and micro and two hook profiles, namely, curved and straight. Impact tests show that modified GLARE with Straight Nano Hooks (SNH) have comparable dynamic responses to the standard GLARE (without hooks), while experiencing much less delamination and fiber damage. Microscopic inspection of the four configurations of modified GLARE also illustrates that SNHs generate modified GLARE with minimal manufacturing defects. The results obtained indicate that SNH is the optimum hook geometry for the development of modified GLARE. It can be considered as an alternative surface treatment for sheet metals in FML development process as it offers a modified version of the material with comparable impact responses to those manufactured by the industrial standard methodology but at a fraction of production cost.