Methodology to Predict Ballistic Penetration and Damage of-Composite Laminated Structures

The objective of the Phase I effort is to demonstrate an experimental/numerical technique for formulating penetration equations and identifying pertinent material parameters to be used in those equations. Although penetration equations for isotropic metals are well developed, such equations are not readily applicable to anisotropic laminated composites, because composite failure is dominated by brittle fracture processes rather than ductile plastic flow. We will develop equations which combine empirical curve fits with physical principles. The equations will primarily be obtained from fits to experimental data points plotted in the form of Phase or Residual Velocity Diagrams. We will supplement the experimental data points with computational data points obtained with the DYNA3D finite element code using a progressive damage model for composites with failure criteria and degradation rules. Important features of this code for penetration applications are element erosion and adaptive slidelines. We will also perform numerical parameter studies to obtain an improved understanding of the physics, and thus identify pertinent material parameters to be used in the penetration equations. The Phase I effort will deliver a prototype stand-alone code for predicting ballistic interaction between projectiles and fragments penetrating laminated composite targets. The program will consist of the penetration equations, databases with default composite and impactor parameters, graphical output, and an advisor.