“…4 c), then form black smoke at the location of detonators, the fireball finally slows down and spreads around. The fireballs reflect the shape of blast waves 32 and change the state of air 33 in the near field, they are non-spherical and have obvious directivity in all cases. Figure 4 Detonation products of repeated tests at 2 ms. ( a ) Case 1.…”
Cylindrical shells are widely used in public buildings and military protection fields, and it has a high risk of terrorist attacks and military attacks, it is of great social benefit to carry out the anti-blast design of cylindrical shells, which needs to consider building shape and the shape of blast waves. In this paper, cylindrical charges in five directions were detonated on the outer ground of the scaled cylindrical shell, blast loads of the cylindrical shell were measured and blast waves were photographed. The variation of blast load is analyzed by combining the test and simulation results, the difference in peak overpressure of the blast waves on the end face between five orientations is nearly twice. The blast loads in the axial direction of cylindrical charges have a secondary peak phenomenon, and the blast loads between the axial direction and radial direction of cylindrical charges change abruptly at a specific angle. The experimental and simulation methods provide a reference for establishing a blast load database of typical buildings.
“…4 c), then form black smoke at the location of detonators, the fireball finally slows down and spreads around. The fireballs reflect the shape of blast waves 32 and change the state of air 33 in the near field, they are non-spherical and have obvious directivity in all cases. Figure 4 Detonation products of repeated tests at 2 ms. ( a ) Case 1.…”
Cylindrical shells are widely used in public buildings and military protection fields, and it has a high risk of terrorist attacks and military attacks, it is of great social benefit to carry out the anti-blast design of cylindrical shells, which needs to consider building shape and the shape of blast waves. In this paper, cylindrical charges in five directions were detonated on the outer ground of the scaled cylindrical shell, blast loads of the cylindrical shell were measured and blast waves were photographed. The variation of blast load is analyzed by combining the test and simulation results, the difference in peak overpressure of the blast waves on the end face between five orientations is nearly twice. The blast loads in the axial direction of cylindrical charges have a secondary peak phenomenon, and the blast loads between the axial direction and radial direction of cylindrical charges change abruptly at a specific angle. The experimental and simulation methods provide a reference for establishing a blast load database of typical buildings.
“…Impulse, für den Fall ohne vorhandene Schutzwand (Schockwellenausbreitung im freien Feld), dargestellt. Zur Berechnung der äquivalenten Masse von TNT wurde ein Umrechnungsfaktor von 1,265 [8] für PETN verwendet. Daraus ergibt sich eine Masse des Explosivstoffs von 4,9 kg TNT‐Äquivalent.…”
In diesem Aufsatz werden experimentelle und numerische Untersuchungen zur Minderung von Explosionslasten auf Gebäude und Menschen durch verschiedene Konfigurationen einer Schutzwand vorgestellt. Die Wandkonstruktion besteht aus einer Gabionenwand mit einem aufgesetzten Leitblech, das mit unterschiedlichen Neigungswinkeln angeordnet wird. Für jede Testkonfiguration wurden drei Versuche durchgeführt. Numerische Modelle wurden entwickelt und anhand der Versuchsdaten validiert. Aus Kosten‐ und Platzgründen wurden Schutzwände mit einer geringen Breite von 2 m in den Versuchen untersucht. Hinter der Wand kommt es hierdurch zur Überlagerung der vertikal über die Oberseite der Schutzwand strömenden Schockwelle mit der seitlich um die Wand strömenden Schockwelle. Neben den in den Versuchen eingesetzten kurzen Wänden wurden lange Wände numerisch simuliert, wie sie in der Praxis benötigt werden. Die numerischen Untersuchungen an der langen Umfassungswand zeigten, dass Leitbleche die Intensität der Schockwelle deutlich reduzieren können. Bezüglich der Schutzwirkung erweist sich die Testkonfiguration mit einer Anordnung des Leitblechs von 45° in Richtung des Explosionsursprungs als wirkungsvollste Maßnahme. Im Vergleich zum Freifeldszenario wird in den untersuchten Bereichen eine Überdruckreduktion (Impulsreduktion) von 55,0 % bis 86,0 % (von 45,7 % bis 63,8 %) erreicht.
“…These studies show that unlike the far-field regime, in the near-field regime a unique EF value for a specific blast parameter cannot represent the real behavior (e.g. Xiao et al, 2019Xiao et al, , 2020. Therefore, in addition to affecting the impulse and pressure values, the EF in the near-field may affect also the spatial distribution of the blast load over the structural element.…”
Section: Introductionmentioning
confidence: 98%
“…These studies show that unlike the far-field regime, in the near-field regime a unique EF value for a specific blast parameter cannot represent the real behavior (e.g. Xiao et al, 2020Xiao et al, , 2019.…”
Detonation of a high explosive close to a structural component results in a blast load that is highly localized and nonuninform in nature. Prediction of structural response and damage due to such loads requires a detailed understanding of both the magnitude and distribution of the load, which in turn are a function of the properties and dimensions of the structure, the standoff from the charge to the structure, and the composition of the explosive. It is common to express an explosive as an equivalent mass of TNT to facilitate the use of existing and well-established semi-empirical methods. This requires calculation of a TNT equivalency factor (EF), that is, the mass ratio between the equivalent mass of TNT and the explosive mass in question, such that a chosen blast parameter will be the same for the same set of input conditions aside from explosive type. In this paper, we derive EF for three common explosives: C4, COMP-B, and ANFO, using an equivalent upper bound kinetic energy approach. A series of numerical simulations are performed, and the resultant magnitudes and distributions of specific impulse are used to derive the theoretical upper bound kinetic energy that would be imparted to a flexible target. Based on the equivalent mass of TNT of each explosive, which is required to impart the same kinetic energy for a given target size and standoff distance as of TNT, the EF is calculated. It is shown that in the near-field, the EFs are non-constant and are dependent on both standoff and target size. The results in the current study are presented in a scaled form and can be used for any practical combination of charge mass, distance from the charge to the target, target size, thickness, and density.
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