Impact of prototype scale effect on the dynamic responses and damage of steel plates under explosions

Scaling model was widely used in engineering to reveal the responses of full-scale prototype model. This study provided insight into the impact of the scale effect on the dynamic response and damage of stiffened and unstiffened steel plates under explosions. A numerical model consider fluid-structure-interaction (FSI) was established using LS-DYNA platform, and the numerical model was verified by the blast test results. Moreover, the scaling factors () equal to 1 (prototype), 1/2, and 1/4, and 1/8, and 1/12 were considered in the study, the scaling effects on the breach size, plastic area, and the deformation shape were analyzed. The results showed that the breach size and plastic area of the scaled model deviated from the ideal results based on the replica law. However, the deformation shapes of scaled-down plates accurately reflected the deformation characteristics of the full prototype plate. The scaling factor significantly influenced the dynamic responses of stiffened and unstiffened steel plates; as the scaling factor () increased, the dimensionless displacement decreased. The results indicated that a smaller led to a larger deviation in response. The influencing factors of the scaling effect were investigated, and it was found that stiffened steel plates were more sensitive to the scaling factor than unstiffened steel plates. By comparing the detonation of cuboid, cylindrical, and spherical explosives blast-loaded onto stiffened steel plates, it was determined that the detonation of cubic explosives caused the most severe scaling effect on stiffened steel plates under blast loads. The study also found that explosive mass and standoff distance influenced the scaling effect of stiffened steel plates under blast loads. Additionally, steel plates in the plastic stage and the critical state between the elastic and plastic stages were particularly sensitive to the scaling effect. Due to the strain rate effect, which can lead to a deviation from the ideal scale law, different steel materials exhibit varying scale sensitivities. Comparing stiffened plates made from Q235, Q345, DH36, and L907A, the order of sensitivity to the scaling factor was: Q235 > Q345 ≈ DH36 > L907A.