Predicting residual properties of impact-damaged thermoplastic laminates after thermal re-consolidation

This study experimentally and numerically investigates the efficacy of thermal re-consolidation repair on thermoplastic composite laminates subjected to low-velocity impacts at energies ranging from 30 J to 70 J. The experimental results show that thermal re-consolidation repairs significantly enhance the compressive strength after impact and the residual strength decreases with the increase in impact energy. Further analysis revealed that the gradual decrease in compressive strength was due to a sharp increase in fiber damage caused by the increase in impact energy. Crucially, thermal re-consolidation effectively repaired delamination and matrix cracks but could not restore fractured fibers. Thus, in the numerical simulations of repaired laminates, the damage model exclusively accounted for impact-induced fiber damage. The simulation results agreed well with experimental data, which demonstrated the validity and accuracy of the numerical model. The validated model was then employed to predict the post-repair compression strength under various impact energies. The results indicate that the strength asymptotically approaches a plateau with increasing impact energy.