scholarly journals Explosion Disaster Distribution Characteristics and Outlet Open-Close Effect of Turning Roadway

2021 ◽  
Vol 2021 ◽  
pp. 1-10
Author(s):  
Pengfei Lv ◽  
Minghua Ju ◽  
Jiaxu Zhang ◽  
Lei Pang ◽  
Kai Yang ◽  
...  
Keyword(s):  
Shock Wave ◽  
Shock Waves ◽  
Human Body ◽  
Distance Effect ◽  
Destructive Effect ◽  
Bending Angle ◽  
Minimal Impact ◽  
Damage Area ◽  
Damage Degree ◽  
Degree Classification

In this study, under the open-close conditions of a roadway outlet, ANSYS/LS-DYNA was used to build models of explosions on roadways with 0° and 90° bending angles, to compare and analyze the shock wave propagation characteristics and variation laws. Combined with the damage degree classification of shock wave overpressure to human body, the destructive effect zoning of explosion in roadway under the condition of opening and closing of roadway entrance was studied. The results showed that as the bending angle increased, the peak overpressure attenuation of the shock waves became prominent, and the arrival time for the same distance increased. The closure of the roadway outlet had a distance effect on the peak overpressure of the shock waves. The explosion shock waves caused the peak overpressure to rise sharply owing to the reflection and stacking effects near the closure. In the far zone of the outlet, the attenuation of the shock waves was too fast and had minimal impact on the peak overpressure. In addition, the existence of the roadway closure increased the damage area and the severity of the blast wave to human body as a whole. With an increase in the bending angle, the damage range and severity decreased.

scholarly journals Explosion disaster distribution characteristics and outlet open-close effect of turning roadway

2020 ◽  
Author(s):  
Pengfei Lv ◽  
Minghua Ju ◽  
Jiaxu Zhang ◽  
Lei Pang ◽  
Kai Yang
Keyword(s):  
Shock Wave ◽  
Shock Waves ◽  
Human Body ◽  
Nonlinear Dynamic Analysis ◽  
Distance Effect ◽  
Distribution Law ◽  
Destructive Effect ◽  
Bending Angle ◽  
Finite Element Program ◽  
Minimal Impact

Abstract In this study, under the open-close conditions of a roadway outlet, the nonlinear dynamic analysis finite element program ANSYS/LS-DYNA was used to build models of explosions on roadways with 0˚ and 90˚ bending angles, to compare and analyse the shock wave propagation characteristics and variation laws. Moreover, the destructive effect of the explosion on the partition was analysed based on the level of damage caused to the human body by shock wave overpressure. The results show that the bending angle has an impact on the space-time distribution law of the explosion shock waves on the roadway. As the bending angle increases, the peak overpressure attenuation of the shock waves becomes prominent, and the arrival time for the same distance increases. The closure of the roadway outlet has a distance effect on the peak overpressure of the shock waves. The explosion shock waves cause the peak overpressure to rise sharply owing to the reflection and stacking effects near the closure. In the far zone of the outlet, the attenuation of the shock waves is too fast and has minimal impact on the peak overpressure. Additionally, overall, the closure of the roadway outlet increases the damage range of the explosion shock waves and the severity of their effect on the human body. With an increase in the bending angle, the damage range and severity decrease. These results can provide a reference for explosion disaster evaluation and prevention.

Investigation of shock-wave deformation history from recovered structure

1986 ◽  
Vol 44 ◽  
pp. 434-435
Author(s):  
M.A. Mogilevsky ◽  
L.S. Bushnev
Keyword(s):  
Shock Wave ◽  
Plastic Deformation ◽  
Dislocation Density ◽  
Shock Waves ◽  
Shock Front ◽  
Single Crystals ◽  
Residual Deformation ◽  
Deformation Structure ◽  
Deformation History ◽  
Deformation Velocity

Single crystals of Al were loaded by 15 to 40 GPa shock waves at 77 K with a pulse duration of 1.0 to 0.5 μs and a residual deformation of ∼1%. The analysis of deformation structure peculiarities allows the deformation history to be re-established.After a 20 to 40 GPa loading the dislocation density in the recovered samples was about 1010 cm-2. By measuring the thickness of the 40 GPa shock front in Al, a plastic deformation velocity of 1.07 x 108 s-1 is obtained, from where the moving dislocation density at the front is 7 x 1010 cm-2. A very small part of dislocations moves during the whole time of compression, i.e. a total dislocation density at the front must be in excess of this value by one or two orders. Consequently, due to extremely high stresses, at the front there exists a very unstable structure which is rearranged later with a noticeable decrease in dislocation density.

Features of spatial shock-wave flows in vapor-gas-liquid mixtures

2014 ◽  
Vol 10 ◽  
pp. 27-31
Author(s):  
R.Kh. Bolotnova ◽  
U.O. Agisheva ◽  
V.A. Buzina
Keyword(s):  
Shock Wave ◽  
High Pressure ◽  
Shock Waves ◽  
Liquid Mixture ◽  
Liquid Mixtures ◽  
Pressure Vessels ◽  
Water Mixture ◽  
Two Dimensional ◽  
Nonstationary Processes ◽  
Two Phase

The two-phase model of vapor-gas-liquid medium in axisymmetric two-dimensional formulation, taking into account vaporization is constructed. The nonstationary processes of boiling vapor-water mixture outflow from high-pressure vessels as a result of depressurization are studied. The problems of shock waves action on filled by gas-liquid mixture volumes are solved.

scholarly journals Nematic Dispersive Shock Waves from Nonlocal to Local

2021 ◽  
Vol 11 (11) ◽  
pp. 4736
Author(s):  
Saleh Baqer ◽  
Dimitrios J. Frantzeskakis ◽  
Theodoros P. Horikis ◽  
Côme Houdeville ◽  
Timothy R. Marchant ◽  
...  
Keyword(s):  
Shock Wave ◽  
Liquid Crystals ◽  
Shock Waves ◽  
Numerical Solutions ◽  
Wave Structure ◽  
Beam Power ◽  
Input Beam ◽  
Shock Wave Structure ◽  
Wave Solutions ◽  
Modulation Theory

The structure of optical dispersive shock waves in nematic liquid crystals is investigated as the power of the optical beam is varied, with six regimes identified, which complements previous work pertinent to low power beams only. It is found that the dispersive shock wave structure depends critically on the input beam power. In addition, it is known that nematic dispersive shock waves are resonant and the structure of this resonance is also critically dependent on the beam power. Whitham modulation theory is used to find solutions for the six regimes with the existence intervals for each identified. These dispersive shock wave solutions are compared with full numerical solutions of the nematic equations, and excellent agreement is found.

scholarly journals Equation of state studies at SILP by laser-driven shock waves

1996 ◽  
Vol 14 (2) ◽  
pp. 157-169 ◽  
Author(s):  
Yuan Gu ◽  
Sizu Fu ◽  
Jiang Wu ◽  
Songyu Yu ◽  
Yuanlong Ni ◽  
...  
Keyword(s):  
Shock Wave ◽  
High Pressure ◽  
Equation Of State ◽  
Shock Waves ◽  
Target Surface ◽  
Shock Adiabats ◽  
Pressure Shock ◽  
Aluminum Target ◽  
Laser Illumination ◽  
The Stability

The experimental progress of laser equation of state (EOS) studies at Shanghai Institute of Laser Plasma (SILP) is discussed in this paper. With a unique focal system, the uniformity of the laser illumination on the target surface is improved and a laser-driven shock wave with good spatial planarity is obtained. With an inclined aluminum target plane, the stability of shock waves are studied, and the corresponding thickness range of the target of laser-driven shock waves propagating steadily are given. The shock adiabats of Cu, Fe, SiO2 are experimentally measured. The pressure in the material is heightened remarkably with the flyer increasing pressure, and the effect of the increasing pressure is observed. Also, the high-pressure shock wave is produced and recorded in the experimentation of indirect laser-driven shock waves with the hohlraum target.

THE EFFECTS OF DIFFERENT PERTURBATIONS ON THE DYNAMICS OF THE ACCRETION DISK AROUND THE BLACK HOLE

2007 ◽  
Vol 22 (10) ◽  
pp. 1875-1898 ◽  
Author(s):  
ORHAN DÖNMEZ
Keyword(s):  
Shock Wave ◽  
Black Hole ◽  
Shock Waves ◽  
Accretion Disk ◽  
Periodic Oscillation ◽  
Single Star ◽  
Special Cases ◽  
Galactic Black Hole ◽  
General Relativistic ◽  
Armed Spiral

We investigate the special cases of the formation of shocks in the accretion disks around the nonrotating (Schwarzschild) black holes in cases where one or few stars perturb the disk. We model the structure of disk with a 2D fully general relativistic hydrodynamic code and investigate a variety of cases in which the stars interacting with the disk are captured at various locations. We have found the following results: (1) if the stars perturb the disk at nonsymmetric locations, a moving one-armed spiral shock wave is produced and it destroys the disk eventually; (2) if the disk is perturbed by a single star located close to the black hole, a standing shock wave is produced while the disk becomes an accretion tori; (3) if the disk is perturbed by stars at symmetric locations, moving two-armed spiral shock waves are produced while the disk reaches a steady state; (4) continuous injection of matter into the stable disk produces a standing shock wave behind the black hole. Our outcomes reinforce the view that different perturbations on the stable accretion disk carry out different types of shock waves which produce Quasi-Periodic Oscillation (QPO) phenomena in galactic black hole candidates and it is observed as a X-ray.

Research on Propagation Numerical Simulation of Blast Shock Waves in Subway Station

2013 ◽  
Vol 380-384 ◽  
pp. 1725-1728
Author(s):  
Yang Hu ◽  
Huai Yu Kang
Keyword(s):  
Numerical Simulation ◽  
Shock Wave ◽  
Experimental Study ◽  
Shock Waves ◽  
Theoretical Basis ◽  
Damage Effect ◽  
Subway Station ◽  
Element Calculation ◽  
Dynamic Finite Element ◽  
Walking Pattern

In this paper, we Research on Propagation Numerical Simulation and damage effect of Blast Shock Waves in Subway Station by using LS-DYNA dynamic finite element calculation program , the results reproduce the formation process of the explosive flow field, and analysis the shock wave waveform, attenuation and walking pattern, provides the theoretical basis for further experimental study.

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