Prediction of Ship Bulkhead Deflection Under Internal Explosion

Internal explosions within ship compartments pose a severe threat to structural integrity. To investigate the plastic dynamic response of ship bulkheads under such loading, this study presents a comprehensive approach integrating experimental testing, numerical simulation, and theoretical derivation. First, a numerical model for shock wave propagation in a confined cabin was established to characterize the complex load distribution. Based on the simulation results, fitting formulas for reflected shock wave overpressure in different bulkhead regions were derived. Subsequently, a simplified theoretical model for predicting plastic deformation was developed based on the principle of energy conservation and the momentum theorem. By utilizing impulse equivalence and constructing a deflection shape function, the plastic dissipation energy—including the bending of plastic hinge lines and in-plane membrane stretching—was analytically solved. To validate the proposed theoretical model, cabin explosion tests using 80g TNT charges were conducted. The results indicate that the theoretical predictions align well with the experimental measurements, with a relative error of approximately 13.8%. This demonstrates that the proposed method provides a rapid and effective tool for predicting the plastic deformation of bulkheads under internal blast loading, offering a practical alternative to time-consuming numerical simulations.