Finite-element simulation for modeling composite plates subjected to soft-body, high-velocity impact for application to bird-strike problem of composite fan blades

We presented a numerical simulation to address the impact-induced deformation and damage of composite plates subjected to soft-body, high-velocity impacts for application to the bird-strike problem of composite fan blades. A new stabilized contact algorithm was developed based on the Lagrange multiplier method to predict appropriate impact forces applied to the plate, in order to solve soft-body impact at high velocity without causing severe numerical instabilities. The bird-strike impact on composite fan blade was simply modeled by discussing the damage characteristics of a unidirectional composite plate. Combining the model of a soft-body impactor with an appropriate contact algorithm, we could capture the transition from the global bending mode at low velocity to the local deformation mode at high velocity, enabling a discussion of the ballistic limit using the damage analysis of the laminate. As the impact velocity increased, the damage in the composite changed from bending-induced matrix-cracking to an intensive fiber-breakage mode causing local shear perforation. The damage mode transition allows us to detect the transition velocity as a ballistic limit, which is one of the critical factors for discussing the bird-strike resistance of composite fan blades.