scholarly journals Determining the degree of pulse absorption of air blast wave by spaced material systems

Author(s):  
Lech Starczewski ◽  
Krzysztof Szcześniak ◽  
Michał Gmitrzuk ◽  
Robert Nyc

The paper presents the results of a study to determine the degree of attenuation of a detonation wave pulse generated by a spherical ceresin-phlegmatized hexogen charge, by spaced material systems. The systems were mounted on a ballistic pendulum and the amount of energy absorbed was determined based on the change in pendulum swing. The spaced panels with absorbing elements, simulated the flat bottom of a vehicle exposed to a single blast.

1981 ◽  
Vol 71 (6) ◽  
pp. 1731-1741
Author(s):  
I. N. Gupta ◽  
R. A. Hartenberger

Abstract An analysis of seismic field data from surface shots in two radically different geologic environments shows significantly different seismic phases at the two sites. At the first site, which has a layered sedimentary section, five distinct phases are observed: the P-wave first arrival; a complex wave train consisting of higher mode Rayleigh waves; a precursor to air-blast wave; the air blast wave; and the air-coupled Rayleigh waves. Records from the second site, overlying an unlayered mass of igneous rocks, show only three distinct seismic phases: the P-wave first arrival; a simple wave train of fundamental-mode Rayleigh and Love waves; and an air blast wave. Peak ground velocity, based on the average of the three largest amplitudes in the surface waves preceding the air blast wave, scales well with yield for both sites. Measurements of peak ground velocity may be used to estimate yields of explosive charges at either site within a factor of about 2 if the source distance is known. The scaling relationship appears to be valid over a wide range of yields and site geological conditions.


2020 ◽  
Vol 87 (5) ◽  
Author(s):  
Anthoni Giam ◽  
William Toh ◽  
Vincent Beng Chye Tan

Abstract The analysis of complex blast scenarios typically requires advanced computational methods such as multi-material Eulerian and coupled Eulerian–Lagrangian (CEL) analysis where Jones–Wilkins–Lee (JWL) equation of state is used to model the explosive material. While multiple sets of empirical JWL parameters for trinitrotoluene (TNT) explosives have been published over the past few decades, there is also a lack of guidelines and comparative studies on their applications for the blast analysis. A standardized description of the explosive material behavior allows for a better interpretation of results from research studies involving different blast scenarios and JWL parameters. In this paper, the authors utilize numerical finite element (FE) simulations to investigate the influence of different TNT JWL parameter sets on the blast wave characteristics of a free-air blast across different scaled distances. Utilizing multi-material Eulerian analysis, a series of spherical free-air blasts involving a 100-kg TNT charge modeled with different TNT JWL parameters are conducted. The blast wave characteristics including the incident overpressure, impulse, and time of arrival (TOA) are benchmarked against the empirical-based Kingery–Bulmash air blast formulations through the conventional weapon effect calculator conwep. It was found that the incident overpressure and impulse are highly sensitive to the JWL parameters, with differences as high as 40% at smaller scaled distances, while the influence on TOA is much less significant. This paper hopes to provide a guide for future users on the appropriate JWL parameter sets to model the air blast events involving TNT explosives.


2013 ◽  
Vol 470 ◽  
pp. 335-339
Author(s):  
Lucie Mynarzová ◽  
Miroslav Mynarz

The contribution compares the response of envelope of chosen structure to the effects of transient load. The load was caused by air blast wave due to deflagration of methane-air mixture. The paper deals with interaction of incident blast wave and envelope structure. Considering blast courses obtained from experiments, two simplified models of load were developed. Load, defined by both load functions, was applied to 3D numerical model of the structure. Calculated result values of deflections of wall elements were compared to experimentally obtained deflections.


2019 ◽  
Vol 123 ◽  
pp. 01008
Author(s):  
Mykola Nalisko ◽  
Valerii Sobolev ◽  
Dmytro Rudakov ◽  
Nataliia Bilan

A technique for evaluation of shock wave impulse after a methane-air mixture explosion is elaborated. The numerical model developed in previous studies has been verified in the laboratory by using laser initiation of explosives and measuring the pressure impulses of explosion products on a ballistic pendulum. To evaluate the mechanical impulse the functional correlations between its magnitude, the swing angle, and the pendulum characteristics have been derived analytically. The reliability of experimental results is ensured by calibrating the sensor that measures the pendulum swing angle and estimating the impulse measurement errors caused by specifics of angle measurements by a digital voltmeter, pendulum axis friction, and the pauses between measurements. Testing the developed technique to evaluate the shock wave impact showed satisfactory consistency of experimental and theoretical results with the momentum deviation below 9%, which confirms model applicability and correct reproducibility of the shock wave propagation process.


2014 ◽  
Vol 548-549 ◽  
pp. 1763-1767
Author(s):  
Hai Jun Wang ◽  
Yong Yao ◽  
Zhao Qiang Zhang ◽  
Xiao Pan Yang ◽  
Yu Ping Zhu

Embedded steel frame concrete blast walls can effectively counteract and dissipation the air-blast wave of the explosion. By contrast widely recognized air-blast wave empirical formula to verify the feasibility of the method of explosion load simplify model numerical simulation calculate the shock wave problems by using the explicit finite element software ANSYS/LS-DYNA and keywords *LOAD_BLAST. Obtained, The results of simplified explosion shock wave load by *load_blast have small difference with the actual explosion model; The destruction of the wall are mainly shear and brittle failure; The ability of Embedded steel frame blast wall resist air-blast wave significantly greater than other wall.


1968 ◽  
Vol 152 (1) ◽  
pp. 103-121 ◽  
Author(s):  
Donald R. Richmond ◽  
Edward G. Damon ◽  
E. Royce Fletcher ◽  
I. Gerald Bowen ◽  
Clayton S. White

Author(s):  
Z. Wang ◽  
X. Gong ◽  
J. Xiong ◽  
H. Yong

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