WAVE PROPAGATION INDUCED BY IMPACT OF FAST-FLYING AIRCRAFT UPON A RIGID TARGET USING SPECIAL GAP FINITE ELEMENT

The shock dynamic response of structures subjected to projectile impact loading has been recognized by engineers as long as a quarter of a century ago. Several computer programs have been develped to evaluate the loading history ( the reaction versus time curve ) for impact projectiles (missiles and aircrafts) impinging against fixed or moving targets. Here, the Finite Element Method with special gap element is used for prediction of reaction vs. time curve as well as the displacement, velocity and acceleration response of different points of the projectile. It is shown that the reaction-time curve at, the interface can be reliably predicted. First a problem of elastic impact of a uniform bar has been solved analytically and numerically and the results showed good agreement. Another problem of practical interest is the dynamic impact of Phantom airplane hitting upon a rigid barrier. This problem is solved with three different options, first with linear elastic material, second with nonlinear elastic-plastic material and third with consideration of large displacement, finite strain plasticity and updated Lagrange analysis. The results of FEM are compared to those obtained w:th the well known Riera and lumped mass approaches.