Smoothed particle hydrodynamics simulation of the submarine structure subjected to a contact underwater explosion

Wang

Sci. China Technol. Sci.

et al. 2019

A process of underwater explosion of a charge near a rigid wall includes three main stages: charge detonation, bubble pulsation and jet formation. A smoothed particle hydrodynamics (SPH) method has natural advantages in solving problems with large deformations and is suitable for simulation of processes of charge detonation and jet formation. On the other hand, a boundary element method (BEM) is highly efficient for modelling of the bubble pulsation process. In this paper, a hybrid algorithm, fully utilizing advantages of both SPH and BEM, was applied to simulate the entire process of free and near-field underwater explosions. First, a numerical model of the free-field underwater explosion was developed, and the entire explosion processfrom the charge detonation to the jet formation-was analysed. Second, the obtained numerical results were compared with the original experimental data in order to verify the validity of the presented method. Third, a SPH model of underwater explosion for a column charge near a rigid wall was developed to simulate the detonation process. The results for propagation of a shock wave are in good accordance with the physical observations. After that, the SPH results were employed as initial conditions for the BEM to simulate the bubble pulsation. The obtained numerical results show that the bubble expanded at first and then shrunk due to a differences of pressure levels inside and outside it. Here, a good agreement between the numerical and experimental results for the shapes, the maximum radius and the movement of the bubble proved the effectiveness of the developed numerical model. Finally, the BEM results for a stage when an initial jet was formed were used as initial conditions for the SPH method to simulate the process of jet formation and its impact on the rigid wall. The numerical results agreed well with the experimental data, verifying the feasibility and suitability of the hybrid algorithm. Besides, the results show that, due to the effect of the Bjerknes force, a jet with a high speed was formed that may cause local damage to underwater structures.

Section: Basic Sph Equationsmentioning

confidence: 99%

“…Chen et al [38] offered a multiphase SPH model for multi-fluid flow with high density ratios. In this paper, based on a volume approximation, a detailed derivation of the modified SPH method [39] for the continuity, momentum and energy equations are given by…”

Section: Basic Sph Equationsmentioning

confidence: 99%

SPH-BEM simulation of underwater explosion and bubble dynamics near rigid wall

Wang

Sci. China Technol. Sci.

et al. 2019

Mathematical Problems in Engineering

“…Many research studies have investigated the effect of shaped charges against underwater targets. For example, Zhang et al [13] established Smoothed Particle Hydrodynamics (SPH) models for single-and double-cylindrical shells (single hull and double hull) and studied the damage caused using Autodyn (Ansys). Kumar et al [14] studied four different cases of air backup, water backup, partial water backup, and free flood water backup through explosion bulge test (EBT) experiments, and they compared the response of a double hull to the proximity explosion with air and water backup using a finite element (FE) model.…”

Section: Introductionmentioning

confidence: 99%

Formation and Penetration Capability of an Annular-Shaped Charge

Wang

Yin

et al. 2021

Shaped charges are widely used in the field of national defense because of their high energy density and strong directivity; however, one of their limitations is that the penetration diameter is small. Compared with a traditional shaped charge, an annular-shaped charge can create a larger penetration aperture at the target, thereby causing more damage to underwater targets. To enhance the damage effect of a shaped charge on an underwater structure, we designed an annular-shaped charge structure. To end this, we first established a velocity calculation model of the liner and analyzed its formation process. The hydrocode software Autodyn was used to simulate the jet formation process. Second, two parameters of the annular liner height and thickness of the bottom and their effect on the annular jet formation were analyzed. Finally, an experiment was conducted to validate the penetration capability of this charge. The experimental results indicate that the annular-shaped charge can penetrate a typical underwater structure and form a large penetration aperture with a diameter of 420 mm, which is 1.4 times the charge diameter. Furthermore, the numerical results show good agreement with the experimental data; only a 1.67% deviation was observed.

“…Shell structures are widely used in naval vessels, aircraft, and tanks due to their special properties, such as simple construction, being light weight, and good bearing capacity [1][2][3][4]. However, shell structures are often subjected to explosion loads or shock waves in practical applications [5][6][7]. It is necessary to investigate the plastic dynamic response, residual deformation, and damage of the thin plate subjected to an explosion load.…”

Section: Introductionmentioning

confidence: 99%

Analysis of the Deformation and Damage of Clamped Square Plates under Near‐Field Explosion Loads

Guan

Hui-pin

et al. 2018

Shock and Vibration

The deformation and damage mechanism of shell structures under near-field explosion loads has been of great significance in the theoretical study of impact dynamics and may serve as a dependable theoretic basis for the antiexplosion design of shell structures. In this paper, the plastic zone and crevasse size of clamped square plates under near-field explosion loads were discussed based on the plastic hinge law and energy theory. The crevasse size of a plate moving at motion modes Ι and ΙΙ under medium load was obtained according to the ultimate plastic strain criterion. Furthermore, the plastic zone under a high load was determined in terms of the movement law of a plastic hinge line. When the applied load ended, the crevasse sizes of the plates at motion modes III and IV were deduced on the basis of the principle of energy conservation. Finally, numerical simulation was used to analyse the deformation and damage mechanism of the shell structures under near-field explosion loads. The theory and method proposed in this paper are verified using ANSYS software and compared with the experimental results. This study verifies the validity of the proposed approach for analysis of the deformation and damage of a clamped square plate under near-field explosion loads.