• Journal of the Korean Society of Marine Environment & Safety
• /
• v.27 no.2
• /
• pp.377-386
• /
• 2021

The A60 class deck penetration piece is a fire-resistant system installed on a horizontal compartment to prevent flame spreading and protect lives in fire accidents in ships and offshore plants. This study deals with approximate optimization using discrete variables for the fire resistance design of an A60 class deck penetration piece using different surrogate models and a genetic algorithm. Transient heat transfer analysis was performed to evaluate the fire resistance design of the A60 class deck penetration piece. For the approximate optimization of the piece, the length, diameter, material type, and insulation density were applied to discrete design variables, and temperature, productivity, and cost constraints were considered. The approximate optimum design problem based on the surrogate models was formulated such that the discrete design variables were determined by minimizing the weight of the piece subjected to the constraints. The surrogate models used in the approximate optimization were the response surface model, Kriging model, and radial basis function-based neural network. The approximate optimization results were compared with the actual analysis results in terms of approximate accuracy. The radial basis function-based neural network showed the most accurate optimum design results for the fire resistance design of the A60 class deck penetration piece.

• Applied Chemistry for Engineering
• /
• v.34 no.4
• /
• pp.421-425
• /
• 2023

The smoke properties of some plastics were investigated, including polymethyl methacrylate (PMMA), polycarbonate (PC), polyvinyl chloride (PVC), and polyacetal. For smoke density, related values of static smoke characteristics were measured using a smoke density tester according to ISO 5659-2. In addition, combustion with and without flame was measured independently. Under the condition of radiant heat of 50 kW/m² using the flame method, the measured value of the maximum specific optical density (D_m) of smoke showed the lowest value for PMMA (401.26) and the highest value for PVC (1345.04). In addition, PMMA (262.82) was the lowest and PVC (1385.43) was the highest in the measured D_m of smoke under the condition of radiant heat of 50 kW/m² in the non-flame method. Smoke generation during combustion of the object is significantly affected by the radiant heat flux, and carbonizable plastics showed a higher amount of smoke than non-carbonizable plastics during combustion. Polymers with aromatic groups in the main polymer chain generated a large amount of smoke because a large amount of char was generated due to thermal decomposition.