Dynamics of Projectiles Launched by a Two-Stage Light-Gas Gun.

摘要

Projectiles launched at hypervelocities at the ballistic ranges of Arnold Engineering Development Center (AEDC) are subject to extreme loads of over 100,000 g's and occasionally fail. The ultimate material strength, in practice, limits the maximum speed to which the projectile can be launched and still remain intact. The projectiles are constructed from a variety of materials, including metals, plastics, and composites, and may undergo large viscoplastic deformations dependent on the strain rate. An understanding of the dynamics of the projectile and its interaction with the light-gas and barrel wall could lead to improved projectile designs and to procedures to reduce the possibility of model failure without degrading the overall performance of the gas gun. This Phase I effort addresses the need for an analytical tool to simulate accurately the projectile dynamic stresses. Under this study, a prototype finite element code has been developed and tested for axisymmetric projectiles to assess the feasibility of conducting realistic simulations. Finite element method, Friction, Hypervelocity, Light-gas gun, Viscoelasticity, Viscoplasticity.