Calculation Methods for Evaluation of Bird Impact on Aircraft Structures

This paper on "Calculation Methods for Evaluation of Bird Impact on Aircraft Structures" was presented at the NAFEMS World Congress on Effective Engineering Analysis - 25-28 April 1999, Newport, Rhode Island, USA.

Summary

This report describes the theoretical determination of the bird impact resistance of a horizontal stabilizer leading edge. The ABAQUS/explicit finite element code was used to simulate the bird strike impact, the bird represented as hydrodynamic-equivalent and the analysis time dependent within a 6 msec period of time.
The material data of the bird were chosen with respect to tested bird substitutes and gained by ‘iterative design loops’. The short time impact behavior of the metallic leading edge is evaluated in two independent material models (perfectly elastic-plastic and elastic-plastic with isotropic hardening), which were used within separate simulation runs.
The failure of the structure was determined by using an energy based approach The bird impacts the structure with an initial amount of kinetic energy; The reduction of the kinetic energy is used to determine the energy absorption capability (EAC) of the structure. This correlates with the penetration velocities of the structure and shows, whether the bird will penetrate the structure.
In addition, the impact forces, calculated within the bird strike simulation, are presented. These forces are compared to experimental results, which are used to illustrate the practicability of the calculation method.