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.

Dynamic Responses of a Cylindrical Shell Subjected to Shock Wave Induced by Underwater Explosion

1997 ◽  
Author(s):  
Zhong Weifang ◽  
Liu Zhongzu
Keyword(s):  
Shock Wave ◽  
Cylindrical Shell ◽  
Underwater Explosion ◽  
Dynamic Responses ◽  
Equilibrium Equations ◽  
Wave Pressure ◽  
Coupled Equations ◽  
Shock Wave Pressure ◽  
Wave Induced ◽  
Interaction Problem

Abstract The dynamic responses of a finite length cylindrical shell submerged in an infinite, inviscid, irrotational, incompressible fluid and subjected to shock waves induced to underwater explosion due to a spherical charge, are investigated in the view of method of modal superposition. Effects of shock wave pressure and hydrodynamic force are considered in shell equilibrium equations. By expanding distribution function of shock wave pressure into Fourier series and using method of Galerkin, the coupled equations of fluid-structure interaction problem are solved numerically. Finally, displacement re sponse of the shell is obtained.

scholarly journals A New Measurement Based on HPB to Measure the Wall Pressure of Electric-Spark-Generated Bubble near the Hemispheric Boundary

2020 ◽  
Vol 2020 ◽  
pp. 1-20 ◽  
Author(s):  
Chunlong Ma ◽  
Dongyan Shi ◽  
Xiongwei Cui ◽  
Yingyu Chen
Keyword(s):  
High Speed ◽  
Underwater Explosion ◽  
Hopkinson Bar ◽  
Wall Pressure ◽  
Experimental Result ◽  
Bubble Collapse ◽  
Pressure Loading ◽  
Sensing Element ◽  
Collapse Pressure ◽  
Experiment System

Direct measurement of the wall pressure loading of the spherical boundary subjected to the near-field underwater explosion is a great difficulty. To investigate the wall pressure caused by electric-spark-generated bubble near a hemispheric boundary, an experiment system is developed. In the method of this experiment, a Hopkinson bar (HPB), used as the sensing element, is inserted through the hole drilled on the hemisphere target and the bar’s measuring end face lies flush with the loaded face of the hemisphere target to detect and record the pressure loading. The semiconductor strain gauges which stick on Hopkinson bar are used to convert the pressure-based signal to the strain wave signal. The bubble in the experiments is formed by a discharge of 400 V high voltage. To validate the pressure measurement technique based on the HPB, an experimental result from pressure transducer is used as the validating system. To verify the capability of this new methodology and experimental system, a series of electric-spark-generated bubble experiments are conducted. From the recorded pressure-time profiles coupled with the underwater explosion evolution images captured by the high-speed camera (HSV), the shock wave pressure loading and bubble collapse pressure loadings are captured in detail at different dimensionless stand-off distances γ from 0.17 to 2.00. From the results of the experiments conducted in this paper, the proposed experiment system can be used to measure the pressure signal successfully, giving new way to study the bubble collapse pressure when the bubble is near a hemispheric boundary. Through the experimental results, the bubbles generated by different dimensionless stand-off distance γ are divided into four categories, and the bubble load characteristics are also discussed.

Relation between Actual Mass and Simulation Mass of Far-Field Underwater Explosion

2011 ◽  
Vol 127 ◽  
pp. 350-354
Author(s):  
Zui Wei Xie ◽  
Xin Yue Wu ◽  
Qiang Wan
Keyword(s):  
Shock Wave ◽  
Curve Fitting ◽  
Underwater Explosion ◽  
Far Field ◽  
Rapid Decay ◽  
Wave Pressure ◽  
Empirical Results ◽  
Shock Wave Pressure ◽  
Simulation Results ◽  
Actual Mass

The far-filed underwater explosive shock wave pressure and impulse is simulated by the FEM code LS-DYNA, and the simulation results are found having rapid decay characteristic through compared with the empirical results. Based on this phenomenon, the relations, whose validity is verified through a computation instance, between simulation mass and actual mass under given initial conditional is obtained by using curve fitting. Using those equations, the accuracy of LS-DYNA to simulate far-field underwater explosive can significantly be increased, thus the ability of this code to simulate far-field underwater explosion is enhanced.

scholarly journals An Experimental Approach to the Measurement of Wall Pressure Generated by an Underwater Spark-Generated Bubble by a Hopkinson Bar

2019 ◽  
Vol 2019 ◽  
pp. 1-14 ◽  
Author(s):  
Xiongliang Yao ◽  
Xiongwei Cui ◽  
Kai Guo ◽  
Yingyu Chen
Keyword(s):  
Numerical Study ◽  
Underwater Explosion ◽  
Experimental System ◽  
Wall Pressure ◽  
Measuring System ◽  
Bubble Collapse ◽  
Pressure Loading ◽  
Hopkinson Pressure Bar ◽  
Sensing Element ◽  
Collapse Pressure

The wall pressure loading due to the underwater spark-generated bubble, having served as an efficient technique to study the underwater explosion, has drawn much attention. Compared with the numerical study of the pressure characteristics, the direct experimental investigation is much rarer. Recently, an improved pressure-measuring system by using a Hopkinson pressure bar as the sensing element is proposed, set up, and validated by the current authors. In this article, the improved methodology and experimental system is used to detect and analyze the pressure loading on the target plate surface due to the underwater spark-generated bubble beneath the plate. A series of experiments with 3 mm, 5 mm, 10 mm, 15 mm, …, 60 mm standoffs are carried out. The experimental results and the related analysis and discussions are presented. Based on the results, the improved methodology can be used to detect the pressure loading due to the spark-generated bubble. There is multipeak oscillation near the peak of the shock pressure loading profile. The peak pressure versus the standoff is also summarized. According to the characteristics of the induced water jet pressure and the bubble-collapse pressure loading given in this article, enough attention should be paid to not only the jet and the first bubble-collapse pressure loadings but also the secondary bubble-collapse pressure loadings especially when the dimensionless distance γ>1.

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.

Influence of a shock-wave pressure gradient on the appearance of a microhardness maximum in α-Fe irradiated by a high-power ion beam

1998 ◽  
Vol 24 (10) ◽  
pp. 819-821 ◽  
Author(s):  
A. N. Valyaev ◽  
A. D. Pogrebnyak ◽  
S. N. Bratushka ◽  
V. I. Lavrent’ev ◽  
S. N. Volkov ◽  
...  
Keyword(s):  
Shock Wave ◽  
Pressure Gradient ◽  
High Power ◽  
Ion Beam ◽  
Wave Pressure ◽  
Shock Wave Pressure

Effects of the aluminum content on the shock wave pressure and the acceleration ability of RDX-based aluminized explosives

2014 ◽  
Vol 116 (14) ◽  
pp. 144906 ◽  
Author(s):  
Z. Q. Zhou ◽  
J. X. Nie ◽  
Z. C. Ou ◽  
J. F. Qin ◽  
Q. J. Jiao
Keyword(s):  
Shock Wave ◽  
Aluminum Content ◽  
Wave Pressure ◽  
Acceleration Ability ◽  
Shock Wave Pressure
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