scholarly journals Damage Characteristics of Polymer Plates under the Impact of the Near-Field and Contact Underwater Explosion

2021 ◽  
Vol 2021 ◽  
pp. 1-17
Author(s):  
Shucan Liu ◽  
Xiaohua Zhao ◽  
Hongyuan Fang ◽  
Xueming Du ◽  
Binghan Xue
Keyword(s):  
Shock Wave ◽  
Near Field ◽  
Underwater Explosion ◽  
Damage Mode ◽  
Distribution Characteristics ◽  
Emulsion Explosive ◽  
Damage Characteristics ◽  
Contact Explosion ◽  
Spatial Distribution Characteristics ◽  
The Impact

In order to study the damage characteristics of polymer plates under the impact of the underwater explosion, the underwater contact and near-field explosion tests of polymer plates were conducted using different explosive quantities. In this paper, eight polymer plates with the size of 500 mm × 500 mm × 60 mm were made, and eight groups of explosion tests were carried out by using the rock emulsion explosive and nonconductive detonators. The damage modes and spatial distribution characteristics of the polymer plate generated by the underwater contact and near-field explosion impact with different explosive quantities are compared and analyzed. In addition, the characteristics of the shock wave propagation in the plates are investigated. It can be observed that the main damage mode of polymer plate is overall damage under the contact underwater explosion. For the near-field explosion, the main damage mode changes to overall failure, and the damage of contact explosion to polymer plate is greater than that of underwater near-field explosion. The polymer plate can reduce and delay the shock wave effectively, but the effect decreases with the increase of explosive quantity in the underwater contact explosion.

scholarly journals A Lab-Scale Experiment Approach to the Measurement of Wall Pressure from Near-Field under Water Explosions by a Hopkinson Bar

2018 ◽  
Vol 2018 ◽  
pp. 1-15 ◽  
Author(s):  
Xiongwei Cui ◽  
Xiongliang Yao ◽  
Yingyu Chen
Keyword(s):  
Shock Wave ◽  
Near Field ◽  
Underwater Explosion ◽  
Experimental System ◽  
Hopkinson Bar ◽  
Wall Pressure ◽  
Pressure Loading ◽  
Target Plate ◽  
Wave Pressure ◽  
Shock Wave Pressure

Direct measurement of the wall pressure loading subjected to the near-field underwater explosion is of great difficulty. In this article, an improved methodology and a lab-scale experimental system are proposed and manufactured to assess the wall pressure loading. In the methodology, a Hopkinson bar (HPB), used as the sensing element, is inserted through the hole drilled on the target plate and the bar’s end face lies flush with the loaded face of the target plate to detect and record the pressure loading. Furthermore, two improvements have been made on this methodology to measure the wall pressure loading from a near-field underwater explosion. The first one is some waterproof units added to make it suitable for the underwater environment. The second one is a hard rubber cylinder placed at the distal end, and a pair of ropes taped on the HPB is used to pull the HPB against the cylinder hard to ensure the HPB’s end face flushes with loaded face of the target plate during the bubble collapse. To validate the pressure measurement technique based on the HPB, an underwater explosion between two parallelly mounted circular target plates is used as the validating system. Based on the assumption that the shock wave pressure profiles at the two points on the two plates which are symmetrical to each other about the middle plane of symmetry are the same, it was found that the pressure obtained by the HPB was in excellent agreement with pressure transducer measurements, thus validating the proposed technique. To verify the capability of this improved methodology and experimental system, a series of minicharge underwater explosion experiments are conducted. From the recorded pressure-time profiles coupled with the underwater explosion evolution images captured by the HSV camera, the shock wave pressure loading and bubble-jet pressure loadings are captured in detail at 5  mm, 10  mm, …, 30  mm stand-off distances. Part of the pressure loading of the experiment at 35  mm stand-off distance is recorded, which is still of great help and significance for engineers. Especially, the peak pressure of the shock wave is captured.

scholarly journals Personnel Casualty Assessment for Explosion in the Subway Platform

2019 ◽  
Vol 2019 ◽  
pp. 1-12
Author(s):  
Jinju Zhang ◽  
Liqiong Wang
Keyword(s):  
Shock Wave ◽  
Explosive Charge ◽  
Assessment Method ◽  
Notch Effect ◽  
Distribution Characteristics ◽  
Wave Load ◽  
Spatial Distribution Characteristics ◽  
Injury Model ◽  
Personnel Safety ◽  
Casualty Assessment

The subway station is easy to be attacked by terrorist bombings, and it will cause heavy casualties. In this paper, a comprehensive casualty assessment method for personnel in the subway structure was established based on the existing personnel injury model. The spatial distribution characteristics of the shock wave suffered by the personnel in the subway platform were obtained. Combined with the comprehensive casualty assessment method, the personnel casualty area for the explosions in the subway platform was divided. The results show that for the same explosive charge, the maximum positive phase impulse generated by the explosion at the edge of the platform is smallest. The “notch effect” for the stair exit will increase the shock wave load. When the explosive is exploded in the center of the platform, the smaller the explosive charge is, the more obvious the “notch effect” is. When the explosive charge reaches 40 kg, the personnel safety area is reduced to a certain extent behind the stair except for the explosion happening at the stair. Also, the higher the shield door is, the larger the safety area behind the stair is.

scholarly journals The Fluid-Solid Interaction Dynamics between Underwater Explosion Bubble and Corrugated Sandwich Plate

2016 ◽  
Vol 2016 ◽  
pp. 1-21
Author(s):  
Hao Wang ◽  
Yuan Sheng Cheng ◽  
Jun Liu ◽  
Lin Gan
Keyword(s):  
Shock Wave ◽  
Failure Modes ◽  
Sandwich Structures ◽  
Numerical Models ◽  
Near Field ◽  
Three Dimensional ◽  
Underwater Explosion ◽  
Bubble Collapse ◽  
Fe Model ◽  
Wave Load

Lightweight sandwich structures with highly porous 2D cores or 3D (three-dimensional) periodic cores can effectively withstand underwater explosion load. In most of the previous studies of sandwich structure antiblast dynamics, the underwater explosion (UNDEX) bubble phase was neglected. As the UNDEX bubble load is one of the severest damage sources that may lead to structure large plastic deformation and crevasses failure, the failure mechanisms of sandwich structures might not be accurate if only shock wave is considered. In this paper, detailed 3D finite element (FE) numerical models of UNDEX bubble-LCSP (lightweight corrugated sandwich plates) interaction are developed by using MSC.Dytran. Upon the validated FE model, the bubble shape, impact pressure, and fluid field velocities for different stand-off distances are studied. Based on numerical results, the failure modes of LCSP and the whole damage process are obtained. It is demonstrated that the UNDEX bubble collapse jet local load plays a more significant role than the UNDEX shock wave load especially in near-field underwater explosion.

scholarly journals Weekend settlements: The case of Sicevacka gorge

2010 ◽  
Vol 90 (2) ◽  
pp. 209-223
Author(s):  
Marija Martinovic ◽  
Ivan Ratkaj ◽  
Mikica Sibinovic
Keyword(s):  
Spatial Distribution ◽  
Statistical Data ◽  
Field Research ◽  
Population Development ◽  
Distribution Characteristics ◽  
Rural Settlements ◽  
Spatial Distribution Characteristics ◽  
Continuous Population ◽  
The 1960S ◽  
The Impact

In this paper we present an analysis of the impact of an intensive process of building rest and recreation houses and the establishment of settlements in the Sicevacka gorge, Serbia, from the 1960s to the beginning of the 20th, century. The analysis is based on field research conducted in 2001/2002nd, as well as official statistical data. In this paper, settlements are defined by their spatial distribution, characteristics of the local position within the existing territory (Atari), and basic trends in development and advanced geospatial changes. Special attention is devoted to the consideration of how the density of temporary settlements (weekend) has impacted the permanent (continuous) population as well as the territorial and population development of existing rural settlements. .

scholarly journals Effect of Computational Parameters on Output Properties of Underwater Explosion by Intelligent Numerical Simulation

2021 ◽  
Vol 2083 (3) ◽  
pp. 032086
Author(s):  
Yonghui Zheng ◽  
Jifeng Wei ◽  
Rui Xiao
Keyword(s):  
Numerical Simulation ◽  
Shock Wave ◽  
Near Field ◽  
Great Influence ◽  
Underwater Explosion ◽  
Propagation Distance ◽  
Rigid Boundary ◽  
Simple Method ◽  
Mesh Density ◽  
Explosion Load

Abstract The computational parameters are of great influence on underwater explosion load. A one-dimensional wedge model is established to analyze the influence of boundary condition (BC), water domain and mesh density on the numerical simulation results. The results show that flowout BC is rigid boundary and transmit BC is not suitable for simulating the collapses phase of bubble pulsation. According to propagation distance of shock wave and its reflected wave, a simple method to calculate appropriate water domain is proposed. A positive correlation between mesh density (λ) and calculated peak pressure of shock wave (P m) is found. When λ tends to infinity, simulated Pm in near field is quite reliable, but the values in relatively far field are lower than empirical results.

Numerical Simulation on the Deepwater Effect of Underwater Explosion Shock Wave

2015 ◽  
Vol 723 ◽  
pp. 290-295
Author(s):  
Zhen Jun Yang
Keyword(s):  
Shock Wave ◽  
Near Field ◽  
Underwater Explosion ◽  
Pressure Curve ◽  
Underwater Shock Wave ◽  
Target Pressure ◽  
Underwater Shock ◽  
Shock Wave Pressure ◽  
Value Changes

By the known shock wave pressure curve, the shock wave of the underwater explosion was simulated loading on a specific target, the stress of the surface of the target, pressure value changes at a point as well as the characteristics response of the target. Through the simulation on the role of near-field characteristics of underwater shock wave acting on the target plate, this paper presents a new way to study the underwater explosion. We can get the pathway graph and its corresponding target corresponding renderings through this method. And all these results can guide the synthesis of new explosive formulations and new substances in the underwater explosives research.

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