<p>To address the limitations of conventional structures in penetration resistance and deflection-based protection, based on the composite armor theory, we designed and fabricated a multilayer bi-directional composite corrugated structure with both anti-penetration and projectile deflection capabilities, and studied the effect of foam filling. A combined experimental and numerical approach was employed to systematically analyze the dynamic response of the structure under ballistic impacts at various positions and velocities. Key aspects such as ballistic limit, failure modes, deflection mechanisms, and energy absorption characteristics were investigated. Results showed that the ballistic resistance of the structure was significantly influenced by impact location, and the gradient thickness design effectively enhanced the deflection effect, increasing the maximum projectile deflection angle by up to 63.72%. Furthermore, compared to the unfilled configuration, foam filling improved the ballistic limit by up to 47.11%, enhanced energy absorption, mitigated structural damage, and increased the maximum deflection angle of the projectile, which exhibited a non-monotonic trend of first increasing and then decreasing with velocity.</p>