EXPERIMENTAL STUDY ON THE EFFECT OF BRASH ICE ON THE LOAD CHARACTERISTICS OF A VEHICLE DURING THE WATER-EXIT

In polar environments, water-exit vehicles are subjected to complex impact and hydrodynamic loads while crossing the ice layer, which poses significant risks to the structural integrity of the vehicle. This paper addresses the characteristics of fluid flow and impact loads during the ice-breaking and water-exit processes of the vehicle. Utilizing a water-exit test system based on a constrained model, ice-breaking image and load measurement system were developed specifically for the vehicle's water-exit. Additionally, we established a preparation technology for crushable frozen model ice, thereby creating a comprehensive test system for the vehicle's water-exit and ice-breaking capabilities. Repeatability tests for the vehicle's water-exit were conducted. Subsequently, using the crushable frozen model ice, we performed water-exit tests with the vehicle under varying sizes and coverage rates. The overall axial force and head pressure time history curves during the vehicle's water-exit process were recorded, allowing for the observation of fluid flow dynamics and the behavior of the ice layer post-impact. The test results indicate that, under conditions of broken ice coverage, the vehicle interacts with the ice layer upon exiting the water, resulting in a significant impact load. This impact load is closely related to the size of the broken ice; larger fragments of broken ice tend to fracture upon being impacted by the vehicle. Furthermore, compared to conditions without broken ice coverage, the vehicle generates more substantial splashing when exiting the water in the presence of broken ice. Additionally, varying degrees of broken ice coverage influence the impact location between the vehicle and the ice. Based on these observations, this paper summarizes three forms of interaction between the vehicle and the broken ice. The research findings elucidate the fluid-solid coupling process and the mechanisms of load formation during the vehicle's water-exit process, providing valuable insights for the study and structural design of water-exit ice-breaking test technology for vehicles and related structures.