Analytical Modeling of Impact Resistance and Damage Tolerance of Laminated Composite Plates

The present study is concerned with a fully analytical model for predicting impact resistance and damage tolerance characteristics of laminated fiber reinforced composite plates. The energy balance for damage development during the impact process is established with the help of a localized deformation field, in which various effects such as the anisotropy of the delaminated sublaminates, elastic property degradation due to matrix cracking, multiple delaminations, and membrane deformation within the damage zone are taken into account. This results in upper and lower bounds of the delamination threshold load and a deflection-dependent critical load for stable delamination propagation. On the basis of the conservation of energy principle, simple relationships are found between the resulting damage area and the impact energy as well as the peak impact load. The global buckling load of damaged rectangular plates is derived from the energy-based stability criterion, and the residual ultimate strength is calculated using the von Karman postbuckling strength theory. The analytical solutions obtained turn out to be capable of providing highly accurate predictions compared with the standard impact and the compression-after-impact experiments of carbon-fiber-reinforced polyetherimide and aromatic polymer composites.