Shock Reduction for Electronic Components Within a Projectile

Electronic components within a projectile are subjected to severe loads over extremely short duration. Failure of these components is likely to have negative implications to the projectile or mission. While experimental data can be helpful in understanding the failure phenomena, collecting such data is usually difficult. There are also limitations on the reliability of sensors under these circumstances. Finite element modeling (FEM) can offer a means to better understand the behavior of these components. It can also be used to design better techniques to mitigate the shocks these components are subjected to. A model of a typical projectile and the gun barrel is presented. The projectile is modified to include a payload of a one-pound mass that represents a typical electronic package, which is supported by a plate. The model, which is subjected to a realistic launch pressure-time history, includes the effects of friction between the gun barrel inner surface and the projectile. The effect of the flexibility of the gun barrel on the vibrations of the electronic package is also considered. This paper proposes using a composite plate, with carbon fibers embedded in an epoxy matrix, to reduce the shocks transmitted to the payload. A parametric study of the effects of varying the thickness of the supporting plate and the fiber volume fraction on accelerations and stresses is included.