Study on the effectiveness of impact factor in underwater explosion model test

The dimensionless quantity is the invariant under the unit conversion, and the only choice to characterize the laws of physics. Aiming at the similarity law of underwater explosion model test, the deficiency of traditional impact factor and the similarity condition of single value of model test are analyzed by using dimensional analysis method and combining with domestic and foreign research. In view of the shortcomings of traditional impact factors, a new impact factor is derived from the perspective of single-value similarity based on the impact dynamic response characteristics of underwater explosion structures. Taking the midship cabin structure of a certain frigate as the prototype, the scale model tests are designed based on the traditional and new impact factors respectively. The effectiveness of the impact factors is evaluated from the aspects of structural damage characteristics, dimensionless deformation deflection, dimensionless velocity and dimensionless acceleration at the center of the structure. To account for the impact of structural characteristics, scale ratio, and proportional distance on the impact factor's effectiveness, various grillage, cabin, and hull girder model tests are conducted using ships of different tonnages as prototypes. The results of the model test, guided by the new impact factor, align well with the prototype test data. In contrast to the traditional impact factor, the model test exhibits greater precision for predicting structural responses, with a broad spectrum of potential applications.