To further study the smoke dispersion and the temperature distribution in ship engine room fires, the fire dynamics solver buoyantReactingFOAM in the software OpenFOAM-10 is used to conduct a numerical simulation study on a pool fire caused by fuel oil leakage in a ship engine room. The applicability of this solver in simulating ship-engine-room-scale fires is validated by comparing it with experimental data. The impact of the mechanical ventilation, fire area, and fire position on the smoke dispersion and the temperature distribution in the ship engine room during the fire are considered in the simulation study, with a focus on the control room and the escape exit. The simulation results of buoyantReactingFOAM agree well with the experimental data. The simulated results of the case study show that for both in the control room and near the escape exit, among the factors of fire position, fire area, and the ventilation situation, the fire position affects the temperature distribution and the smoke dispersion most heavily, followed by the fire area and then the ventilation situation, which has the least influence on them. But, compared to the control room, the influence degree of the ventilation air velocity in the escape exit is larger than that in the control room. With an increase in the fire area, the spread rate of high temperature and high smoke concentration increases. With an increase in the ventilation air velocity, the aggregation degree of smoke and temperature decreases, but its decreasing range is very small when the ventilation air velocity is larger than 2 m/s.

Ship structures may collapse or be severely deformed during a fire. To precisely assess the post-fire structural integrity of ships, in this study, a thermal–mechanical coupling data interface was created, employing a significant eddy simulation algorithm for fire dynamics and a technique to analyze the structural thermal–mechanical coupling reaction. PyroSim was utilized to build a fire scenario, exporting 3D data through the device’s own program, and then the ANSYS thermal–mechanical coupling model was employed to study the spatial temperature distribution under fire-induced conditions. Data from the three-dimensional spatial temperature field served as the boundary condition for the determination of the structural temperature burden. Building on this, an analysis was conducted on the structural response of the intricate two-story interior compartment under fire conditions. The results showed that the location of the fire source and the structural distribution of the mechanical equipment inside the cabin had a great influence on the temperature and combustion heat, followed by the ventilation conditions, while the temperature variations in the parallel dual fuel tanks were greatly influenced by the stack effect. By comparing the stress and strain of the two-layer cabin under normal and fire conditions, the damage and mechanisms associated with important positions in the cabin under fire conditions were revealed.

In order to analyze the explosion risk of the engine room, this paper uses CFD software to simulate the LNG leakage process in the engine room of the ship, and uses the combustible gas cloud obtained from the leakage simulation to simulate the explosion, analyzing its combustion and explosion dynamics. On the basis of previous studies, this paper studies the coupling of leakage and explosion simulation to ensure that it conforms to the real situation. At the same time, taking explosion overpressure, explosion temperature, and the mass fraction of combustion products as the breakthrough point, this paper studies the harm of explosion to human body and the influence of ignition source location on the propagation characteristics of LNG explosion shock wave in the engine room, and discusses the influence of obstacles on gas diffusion and accumulation. The results show that the LNG leakage reaches the maximum concentration in the injection direction, and the obstacles in the cabin have a significant effect on the diffusion and accumulation of gas. In the explosion simulation based on the leakage results, it can be determined that the shape of the pressure field generated by the explosion is irregular, and the pressure field at the obstacle side has obvious accumulation. Finally, in order to reduce the explosion hazard, the collaborative strategy of modular layout, directional ventilation, and gas detection is proposed, which provides ideas for the explosion-proof design of the cabin.

Accurately detecting and tracking cracks on construction materials, such as concrete and rock surfaces, is of paramount importance in the field of structural engineering and materials science. The presence and propagation of cracks in these materials can have significant implications for structural integrity and safety, making it crucial to develop robust methods for crack detection and tracking. This work explores the application of computer vision and deep learning algorithms in the visual recognition and prediction of crack propagation trajectories in construction materials. Specifically, a Split Hopkinson Pressure Bar system and a static compression loading platform were constructed to simulate fracture processes in concrete and rock materials. The high-speed camera was used to capture the fracture process as a video or image sequence. An automatic pixel-level crack segmentation method was proposed to extract cracks at critical moments within the fracture video. Subsequently, the Long Short-Term Memory network was employed to learn temporal patterns and dependencies within the crack segmentation masks across consecutive frames. By leveraging the learned temporal patterns, the network can estimate how cracks will evolve and propagate in subsequent frames. The proposed method has potential applications in assessing structural integrity, understanding fracture mechanisms, and informing maintenance and repair decisions.

In the maritime industry, hydrogen fuel cell ships demonstrate significant potential for development due to their environmental friendliness and high efficiency. However, the risks of fire and explosion caused by hydrogen leakage pose severe challenges to their safety. To enhance the safety of hydrogen fuel cell ships and mitigate the explosion hazards caused by leakage, this study employs the XiFoam solver in the OpenFOAM v9 to establish an explosion model for a full-scale hydrogen fuel cell compartment within a hydrogen fuel cell ship. The model simulates the transient explosion process following high-pressure hydrogen leakage under varying initial hydrogen concentrations and premixed fuel conditions. By analyzing the temporary evolution of temperature distribution, flame front propagation, and explosion pressure, the study provides a comprehensive understanding of the safety implications of hydrogen leakage at different locations within the fuel cell. Specifically, increasing the hydrogen concentration from ΦH₂ = 0.10 to ΦH₂ = 0.18 and ΦH₂ = 0.20 significantly elevates the overpressure peak and accelerates the flame speed from 250 m/s to 370 m/s, with local pressure gradients approaching the deflagration to detonation transition threshold. The simulation results contribute valuable insights into optimizing hydrogen fuel cell design, formulating effective fire safety strategies, and improving overall ship safety.

To investigate the propagation of explosion shock waves within a ship’s engine room, a two-story engine room of a cargo ship was selected as the research object. The BlastFOAM solver in OpenFOAM-9 software was utilized to conduct numerical simulations of the explosion dynamics in the engine room. The results demonstrate that the explosion impact force escalates with the quantity of explosives. Following a liquefied natural gas (LNG) explosion, the shock waves exerted on the ventilation duct and control room are significantly stronger in terms of maximum pressure and intensity compared with those generated by a naphtha explosion. Comprehensive analyses of shock wave pressure distribution, structural damage, and energy absorption reveal that the centralized control room sustains the most severe damage from shock waves, while the ventilation ducts are also significantly impacted. The mechanical equipment absorbs the majority of the shock wave impact while reflecting a minor portion, leading to the intersection of direct and reflected waves. This study provides valuable insights for enhancing the explosion resistance of ship engine rooms, optimizing equipment layout within cabins, and improving the structural resilience of cabin designs.