EXPERIMENTAL CHARACTERIZATION AND NUMERICAL SIMULATION OF IMPACT DAMAGE IN COMPOSITE LAMINATES

摘要

A new experimental technique is developed to determine the onset and evolution of delamination in fiber-reinforced composites. The configuration uses a split-Hopkinson bar for low-velocity impact loading and two Polytec laser vibrometer systems for real-time monitoring of the initiation and progression of delamination. The experiment allows the histories of load, displacement, and velocity of impacted specimens to be recorded and analyzed. Numerical simulations are conducted using a cohesive finite element method. The method employs a cohesive zone model to simulate in-ply cracking and interlaminar delamination and a transversely isotropic, elastic model to characterize the bulk behavior of each ply. The simulations provide time-resolved characterization of damage during the impact loading. The time at which delamination is detected decreases as the impact velocity is increased, and delamination is detected at similar surface displacements. The progression of damage changes as the bonding strength between plies is increased. The speed of delamination decreases as the bonding strength is increased.