A Simple Model for the Prediction of the ...

In the present work, an attempt is made to develop a simple semi-empirical model for prediction of the ballistic-limit of thick-section composite laminates when subjected to a normal impact by a solid (right circular cylinder) projectile (made of a hard enough material to resist plastic deformation). Towards that end, the projectile/composite-laminate interaction process is divided into three distinct phases: (a) a short-term, shock-wave dynamics controlled (initial) Phase 1; (b) a relatively-longer, composite-laminate material deformation/damage/failure controlled (intermediate) Phase 2; and (c) a structural-vibration dominated (final) Phase 3. Projectile/composite-laminate interaction within Phase 1 is analyzed using the theory of planar, longitudinal shock-waves which yielded the reactive force acting on the projectile as a function of the projectile forward displacement. Within the interaction Phases 2 and 3, on the other hand, the reactive force vs. projectile forward displacement relation is obtained using the results (properly modified to include the dynamic effects) of quasi-static punch-shear tests (at varying support-span over punch-diameter ratios). The ballistic-limit results yielded by the model are compared with their finite-element analysis counterparts and a reasonable agreement is observed.