Experimental Contribution to the Modeling of Shock Propagation Induced by a Linear Pyrotechnical Source

2008 ◽  
Vol 51 (1) ◽  
pp. 122-145 ◽  
Author(s):  
Christelle Collet ◽  
Philippe Chabin ◽  
Henri Grzeskowiak
Keyword(s):  
Shock Wave ◽  
Wave Propagation ◽  
High Speed ◽  
Composite Plates ◽  
Shock Wave Propagation ◽  
Shock Propagation ◽  
Mechanical Responses ◽  
Space Agency ◽  
Out Of Plane ◽  
Space Launcher

In recent years, the phenomena occurring during shock wave propagation in spatial structures have been studied to characterize more accurately and to minimize the effects of pyrotechnical sources. As part of a program managed by the Centre National d'Etudes Spatiales (CNES, the French space agency), SNPE Matériaux Energétiques (SME) and MBDA France collaborated in a study to understand the mechanisms of shock wave propagation induced by the detonation of a linear pyrotechnical source. The focus of the study was on structures representative of space launcher structures such as those used for the Ariane 5 launcher. Various experiments were performed with metallic and composite plates, and two types of measurement devices (strain gauges and accelerometers) were investigated. Additional out-of-plane velocity and displacement measurements were provided by laser vibrometers, and displays of the separation of the plates were provided by a high-speed camera (up to 4800 feet/second). Signals treatment provided bending and compression strain describing plate mechanical responses. The apparatus used and the associated concerns that arose during the firings also are discussed.

Numerical Study on Shock Wave Propagation with Obstacles during Methane Explosion

2010 ◽  
Vol 33 ◽  
pp. 114-118 ◽  
Author(s):  
Zhi Ming Qu
Keyword(s):  
Shock Wave ◽  
Wave Propagation ◽  
Velocity Gradient ◽  
High Speed ◽  
Numerical Study ◽  
Shock Wave Propagation ◽  
Gradient Field ◽  
Shock Propagation ◽  
Mixture Flow ◽  
Methane Mixture

During shock wave propagation in the pipeline, the flow field of speed, pressure and temperature is evenly distributed. If there are obstacles, then the flow will be changed while the velocity gradient is formed near the obstacles. Passing through the obstacles, a high-speed gradient of the unburned methane mixture flow is established. While reaching the obstacle, the shock wave surface is rapidly stretched to increase the significant transmission speed. Propagating in the gradient field, the shock wave will be stretched and folded. The deformation of shock wave causes consumption of fuel and oxygen in greater unburned methane surface, which results in heat release rate increasing and faster shock propagation. In conclusion, shock wave causes larger advection speed in front of the unburned methane mixture, increasing flow velocity gradient further and leading to more intense shock wave propagation.

scholarly journals Discrete Element Simulation of Elastoplastic Shock Wave Propagation in Spherical Particles

2011 ◽  
Vol 2011 ◽  
pp. 1-9 ◽  
Author(s):  
M. Shoaib ◽  
L. Kari
Keyword(s):  
Shock Wave ◽  
Wave Propagation ◽  
Dynamic Loading ◽  
Discrete Element ◽  
Particulate Material ◽  
Shock Wave Propagation ◽  
Spherical Particles ◽  
Shock Propagation ◽  
Practical Applications ◽  
Loading Effects

Elastoplastic shock wave propagation in a one-dimensional assembly of spherical metal particles is presented by extending well-established quasistatic compaction models. The compaction process is modeled by a discrete element method while using elastic and plastic loading, elastic unloading, and adhesion at contacts with typical dynamic loading parameters. Of particular interest is to study the development of the elastoplastic shock wave, its propagation, and reflection during entire loading process. Simulation results yield information on contact behavior, velocity, and deformation of particles during dynamic loading. Effects of shock wave propagation on loading parameters are also discussed. The elastoplastic shock propagation in granular material has many practical applications including the high-velocity compaction of particulate material.

scholarly journals Experimental Study on Shock Wave Propagation of the Explosion in a Pipe with Holes by High-Speed Schlieren Method

2020 ◽  
Vol 2020 ◽  
pp. 1-9
Author(s):  
Gang Zhang
Keyword(s):  
Shock Wave ◽  
Wave Propagation ◽  
High Speed ◽  
Experimental System ◽  
Test System ◽  
Shock Wave Propagation ◽  
Oblique Shock Wave ◽  
Schlieren Method ◽  
Wave Fronts ◽  
Blast Energy

The shock wave propagation of the explosion in a pipe with holes was studied by a high-speed schlieren experimental system. In the experiments, schlieren images in the explosion were recorded by a high-speed camera from parallel and perpendicular orientations, respectively, and the pressure in the air was measured by an overpressure test system. In parallel orientation, it is observed that the steel pipe blocks the propagation of blast gases, but it allows the propagation of shock waves with a symmetrical shape. In perpendicular orientation, oblique shock wave fronts were observed, indicating the propagation of explosion detonation along the charge. Shock wave velocity in the hole direction is larger than that in the nonhole direction, indicating the function of holes in controlling blast energy, that is, leading blast energy to hole direction. Furthermore, the function of holes is verified by overpressure measurements in which peak overpressure in the hole direction is 0.87 KPa, 2.8 times larger than that in the nonhole direction. Finally, the variation of pressure around the explosion in a pipe with holes was analyzed by numerical simulation, qualitatively agreeing with high-speed schlieren experiments.

High Speed Photography For Studying The Shock Wave Propagation At High Mach Numbers Through A Reflection Nozzle

1979 ◽  
Author(s):  
S. G. Zaytsev ◽  
E. V. Lazareva ◽  
A. V. Mikhailova ◽  
V. L. Nikolaev-Kozlov ◽  
E. I. Chebotareva
Keyword(s):  
Shock Wave ◽  
Wave Propagation ◽  
High Speed ◽  
Shock Wave Propagation ◽  
High Speed Photography ◽  
Mach Numbers ◽  
High Mach

scholarly journals Study of laser-driven shock wave propagation in Plexiglas targets

1992 ◽  
Vol 10 (1) ◽  
pp. 201-211 ◽  
Author(s):  
L. J. Dhareshwar ◽  
P. A. Naik ◽  
T. C. Kaushik ◽  
H. C. Pant
Keyword(s):  
Shock Wave ◽  
Wave Propagation ◽  
High Speed ◽  
Second Harmonic ◽  
Optical Probe ◽  
Shock Wave Propagation ◽  
Hydrodynamic Simulation ◽  
One Dimensional ◽  
Laser Beam Irradiation ◽  
Shock Fronts

An experimental study of laser-driven shock wave propagation in a transparent material such as Plexiglas using a high-speed optical shadowgraphy technique is presented in this paper. A Nd:glass laser was used to produce laser intensity in the range 1012-1014 W/cm2 on the target. Optical shadowgrams of the propagating shock front were recorded with a second-harmonic (0.53-μm) optical probe beam. Shock pressures were measured at various laser intensities, and the scaling was found to agree with the theoretically predicted value. Shock pressure values have also been obtained from a one-dimensional Lagrangian hydrodynamic simulation, and they match well with experimental results. Shadowgrams of shock fronts produced by nonuniform spatial laser beam irradiation profiles have shown complete smoothing when targets with a thin coating of a material of high atomic number such as gold were used. Shock pressures in such coated targets are also found to be considerably higher compared with those in uncoated targets.

Molecular Dynamics Simulations of Shock Propagation and Spallation in Amorphous Polymers

2021 ◽  
pp. 1-28
Author(s):  
M. A. N. Dewapriya ◽  
Ronald Miller
Keyword(s):  
Shock Wave ◽  
Molecular Dynamics ◽  
Wave Propagation ◽  
Indirect Method ◽  
Direct Method ◽  
Spall Strength ◽  
Amorphous Polymers ◽  
Shock Wave Propagation ◽  
Surface Velocity ◽  
Shock Propagation

Abstract We conducted large-scale molecular dynamics (MD) simulations of shock wave propagation and spallation in amorphous polyurethane and polyurea. First, we computed the shock Hugoniot of the polymers using the multiscale shock technique and compared them with available experimental data to establish the upper limit of the shock pressure that can be accurately modeled using a non-reactive interatomic force field. Subsequently, we simulated shock wave propagation in the polymers, varying the shock particle velocity from 0.125 km/s to 2 km/s. A remarkable similarity in the shock behavior of polyurethane and polyurea was observed. The spall strength of each sample was computed by two methods: (a) the indirect method (based on the free surface velocity history)—accessible in experiments, and (b) a direct method (based on the atomic stresses in the region of spallation)—accessible only through MD. The results reveal that the tensile strength computed from the indirect method is consistently smaller than the value obtained from the direct method. Moreover, the strength computed from the indirect method shows a noticeable agreement with the fracture nucleation stress. Our results provide novel molecular-level insights into the spallation mechanisms of amorphous polymers, which could facilitate the design of polymers for structural barrier applications.

Optical Diagnostics for Energetic Materials Research

2016 ◽  
Author(s):  
Michael J. Hargather ◽  
Joshua L. Smith ◽  
James Anderson ◽  
Kyle Winter
Keyword(s):  
Shock Wave ◽  
Wave Propagation ◽  
Shock Waves ◽  
High Speed ◽  
Optical Diagnostics ◽  
Shock Wave Propagation ◽  
Field Scale ◽  
Schlieren Imaging ◽  
Image Field ◽  
Explosive Events

Optical diagnostics including schlieren, shadowgraphy, and background-oriented schlieren (BOS) are used to visualize shock waves and compressible flow phenomena present in energetic and explosive events. These techniques visualize refractive index variations to obtain a range of qualitative and quantitative information. A one-dimensional explosively-driven shock tube facility is used with schlieren imaging to measure shock wave propagation speeds from explosive-thermite mixtures. The schlieren imaging visualizes turbulent flow structures in the expanding product gas region. An imaging spectrometer is paired with the schlieren imaging to quantify the mixing of the explosive product gases with the ambient environment. Shadowgraphy is applied to image field-scale explosive tests. The shadowgraph images reveal shock waves, fragment motion and speed, and the motion of product gases. BOS is a modern technique for visualizing refractive fields via their distortion of a background pattern. Here the technique is applied to image field-scale explosive events using the ambient background of the test pad. The BOS images clearly show shock wave propagation and reflection from surfaces, which is not clearly visible in the raw high-speed digital images.

Phenomenological analysis of shock-wave propagation in weakly ionized plasmas

AIAA Journal ◽  
1998 ◽  
Vol 36 ◽  
pp. 816-822
Author(s):  
Igor V. Adamovich ◽  
Vish V. Subramaniam ◽  
J. W. Rich ◽  
Sergey O. Macheret
Keyword(s):  
Shock Wave ◽  
Wave Propagation ◽  
Phenomenological Analysis ◽  
Shock Wave Propagation ◽  
Ionized Plasmas ◽  
Weakly Ionized

scholarly journals Observation of the shock wave propagation induced by a high-power laser irradiation into an epoxy material

2013 ◽  
Vol 46 (23) ◽  
pp. 235501 ◽  
Author(s):  
Romain Ecault ◽  
Laurent Berthe ◽  
Michel Boustie ◽  
Fabienne Touchard ◽  
Emilien Lescoute ◽  
...  
Keyword(s):  
Shock Wave ◽  
Wave Propagation ◽  
Laser Irradiation ◽  
High Power ◽  
Shock Wave Propagation ◽  
High Power Laser ◽  
Power Laser ◽  
Epoxy Material
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