<p>Experimental studies were conducted on two high-strength steel plate-frame structures with different truss spacings under various impact velocities to investigate the dynamic mechanical properties of hull plate-frame structures under drop weight impact. The results showed that decreasing the main beam spacing can effectively increase the structural stiffness, reduce the maximum deformation, and increase the damage range. Furthermore, to simulate the impact tests accurately, static and dynamic tensile tests at different strain rates were carried out, and the Cowper-Symonds model parameters were fitted via experimental data. The material properties obtained from the tensile tests were used as inputs for numerical simulations with the numerical results coincide with the experimental results. A systematic analysis and discussion were conducted on the effects of truss spacing and truss width on the dynamic response of the reinforced plates, and an optimal range for the ratio of truss spacing to truss width was proposed. In addition, a mesh size sensitivity analysis for ship hull plate frame collision simulations was performed. The applicability of the EPS, MMC, and RTCL failure criteria in the simulation of plate-frame structures was investigated via finite element simulations of falling weight impact tests. The research findings provide a reference for ship hull structure design and resilience assessment.</p>