Modeling the Effects of Underwater Detonation Wave

Abstract

Minehunters are subjected to specific sea loads due to waving and dynamical impacts associated with underwater explosion. Sea waving can be sufficiently exactly modeled by means of statistical methods. Much more problems arise from modeling impacts due to underwater explosion. Knowledge of a character of impulse loading which affects ship shaft line can make it possible to identify potential failures by means of on-line vibration measuring systems. The problem of influence of sea mine explosion on hull structure is complex and belongs to more difficult issues of ship dynamics. Underwater explosion is meant as a violent upset of balance of a given system due to detonation of explosives in water environment. A paper presents a proposal of identification of a degree of hazard the ships hull forced from underwater explosion. A theoretical analysis was made of influence of changes of hull structure in vicinity of hull. The main problem of naval vessels is a lack of dynamical requirements of stiffness of the hull. Modeled signals and hull structure were recognized within sensitive symptoms of three sub models: model of hull structure, model of impact and model of propulsion system. All sub models allow testing forces and their responses in vibration spectrum using SIMULINK software and FEM models.

A Method for Identification of Non-Coaxiality in Engine Shaft Lines of a Selected Type of Naval Ships

“…The first group was used for determination of central point and radius of five-dimensional clusters of serviceability and unserviceability states identified for each of the PDS groups, separately. Coordinates of central points of the clusters were calculated according to the expression (6), and their radiuses -on the basis of the relation (7): (6) where : CCP R -central point of the cluster of the reliability state R for a given PDS group; R -reliability state equivalent to serviceability state and unserviceability state; -mean value of signal energy calculated for a given PDS group for the reliability state R; -mean value of mean signal power calculated for a given PDS group for the reliability state R; -mean value of abscissa of signal square gravity centre calculated for a given PDS group for the reliability state R; -mean value of square variance calculated for a given PDS group for the reliability state R; -mean value of distance from reference signal calculated for a given PDS group for the reliability state R. (7) where: CR R -cluster radius for a given PDS group for the reliability state R; R -reliability state equivalent to serviceability state and non-serviceability state;…”

“…Each of the files comprised values of vibration parameters for a given ship, shaft line system, measurement point and rotational speed. As a result of the conducted investigations 150 files were obtained after elimination, from the analysis, of those comprising erroneous data [7].…”

“…For developing the method in question the investigations were conducted in actual service conditions of the considered propulsion systems , which, based on results of measurements, were verified by means of R2 coefficient and model simulation results [7]. The tests were performed on the basis of assessment of selected parameters of propulsion systems on 207P minesweepers (whose image is shown in Fig.…”

Comparison of Two Procedures in Application of Numerical Simulation of Shallow Water Explosion in Multi-material Media

“…As a continuous process, there are specific characters and connections and interactions between the spreading process of shock wave and the loading effect of bubble pulsation process, and each process has different fitness for specific problems. Now MSC.DYTRAN and LS-DYNA are widely used in the simulation research of explosion at numerical simulation of underwater explosion [1][2][3][4][5][6][7][8]. To compare and analyse the difference and specific characters of them in shallow water explosion simulation, it is significant for further research of the damage effects that shallow water explosion has on structures with different structure characters and working conditions.…”

Comparison of Two Procedures in Application of Numerical Simulation of Shallow Water Explosion in Multi-material Media

“…As a continuous process, there are specific characters and connections and interactions between the spreading process of shock wave and the loading effect of bubble pulsation process, and each process has different fitness for specific problems. Now MSC.DYTRAN and LS-DYNA are widely used in the simulation research of explosion at numerical simulation of underwater explosion [1][2][3][4][5][6][7][8]. To compare and analyse the difference and specific characters of them in shallow water explosion simulation, it is significant for further research of the damage effects that shallow water explosion has on structures with different structure characters and working conditions.…”