AbstractThe present study combines the advantages of both stainless steel and lightweight high-ductility cement composite (LHDCC) to develop a durable stainless steel–LHDCC composite for marine protective structures. Firstly, the study conducts an impact test program by the drop-hammer test machine to investigate the flexural impact performance of the composite beam. Three failure modes are captured: (1) flexural failure with bond-slip of steel–concrete interface, (2) flexural failure without bond-slip of steel–concrete interface, and (3) shear failure. The dynamic responses including the impact force, reaction force, inertia force, and displacement responses are analyzed in detail. The effects of stud spacing, concrete core thickness, stud type, and concrete layer number on the impact response and failure mode are investigated. Then, the study adopts LS-DYNA to simulate the dynamic behavior of the composite beam under different impact load scenarios. The numerical results are in good agreement with the test results. The bending moment and shear distribution of the composite beam and the influences of impact momentum and impact energy on the dynamic responses are analyzed based on the FEM results. Finally, the study proposes a trilinear load-displacement relationship considering the effects of strain rate and degree of composite action, which is incorporated into the modified single-degree-of-freedom (SDOF) model to predict the impact responses. The results show that the predictive results can well reproduce the displacement-time response and peak displacement of the composite beam.