Numerical analysis of thin-walled shaft perforation by projectile

The impact of a 7.62 NATO projectile on the Al 6061-T4 shaft of the tail rotor transmission of a helicopter is studied in detail in order to identify the effect on the residual strength of the component. The investigation is carried out numerically by means of the finite element method, adopting classical von Mises plasticity in conjunction with a detailed experimental characterization of the mechanical behaviour of the material at different strain rates. In order to validate the method, the results of further analyses simulating the impact of projectiles on moving flat targets are compared with previously published experimental data.