An experimental and numerical study of the dynamic response of a free–free aluminum beam under high velocity transverse impact

Experiments and numerical simulations on the dynamic behavior of free–free aluminum beams subjected to high velocity transverse impact were performed using single-stage light gas gun and nonlinear finite element program, LS-DYNA. A cylindrical free–free beam with a diameter of 30 mm is impacted symmetrically and asymmetrically by a cylindrical aluminum projectile with a diameter of 10 mm in the present experiment. The lengths of the beam and projectile are 150 mm and 20 mm, respectively. It is shown that the responses of free–free beam include elastic–plastic deformation, structural failure and fragmentation. The number of fragments, the local deformation and the mass dissipation of the free–free beam increase linearly with the increase of the initial impact velocity of the projectile. However, the non-dimensional velocity at the central point of the free–free beam decreases with the increase of the initial impact velocity of the projectile and is independent of the impact location. It is found that the dependence of the kinetic energy of the free–free beam on the impact velocity of the projectile is similar to the dependence of the maximum velocity at the central point of the beam on the impact velocity of the projectile. Energy partitions are further predicted. For example, when impact velocity is 400 m/s, the ratio of kinetic energy of the beam to impact energy is 3.3 J while the ratios due to plastic energy dissipation and fragmentation are 15 J and 54% respectively. The rest remains in projectile. It is found that the energy partitions in high velocity impact case are nearly independent of impact location, which is different from those subjected to low velocity impact.