The work is based on the experimental activities developed to investigate the behavior of fiber metal laminate (FML) materials used for very critical structural components, such as leading edge panels that must satisfy a series of requirements defined in terms of structural resistance, applying impact loads at different speeds, arising, for example, from birdstrike on wing leading edge. The experimental tests have been carried out on some panels manufactured by Alenia Aeronautica in the context of a national project, that had the aim to identify the material that defines the best solution in terms of weight and performance to realize a leading edge that was able to be resistant at the birdstrike requirements. The first part of work presents an extensive campaign of tests performed to determine stiffness and strength properties on FML (trade name GLARE). The experiments considered the static tests useful to determine the stress-strain curve; the dynamic tests at different strain rates, and different impact tests to evaluate the threshold energy that correspond to a visible impact damage on the coupon. Subsequently, several tests were performed on two different types of joints that were mechanically tested to determine strength properties at a different strain rate. In the second part of this work, the experimental tests have been reproduced numerically with the aim of validating models able to correctly simulate the phenomenon in question, obtaining a satisfactory numerical-experimental correlation. In the present work the guidelines for the future development of similar numerical models have been traced and advantages and disadvantages of birdstrike modeling have been highlighted and numerical activities allowed to define the parameters of the material and to improve the design rules for a leading edge subjected to the birdstrike.
Guida, M., Marulo, F., Meo, M., & Russo, S. (2012). Experimental tests analysis of fiber metal laminate under birdstrike. Mechanics of Advanced Materials and Structures, 19(5), 376-395. https://doi.org/10.1080/15376494.2010.542273