Shock Wave Power Characteristics of Cylindrical Explosives with Elliptical Cross-section

doi:10.12382/bgxb.2024.0969

Abstract

Abstract:

To explore the explosive shock wave characteristics of typical cylindrical explosives with elliptical cross-section,an experiment on the static explosion of variable-section cylindrical explosives in free field is conducted,and a corresponding numerical simulation model is established.The reliability of the numerically simulated results is verified by comparing with the experimental results.The explosions of cylindrical explosives with different cross-sectional shapes in free field are numerically simulated to investigate the influence of cross-sectional shape on the power characteristics of explosive shock waves.The research results indicate that the explosive shock wave generated by the cylindrical explosives with elliptical cross-section produces a wave system structure similar to that generated by the cylindrical explosives with a circular cross section,but there are differences in the propagation characteristics of shock wave at different azimuth angles.The peak overpressure,maximum impulse,and shock wave velocity in the short-axis direction are all greater than those in the long-axis direction.For elliptical cross-section explosives with different aspect ratios of long axis to short axis,the greater the aspect ratio is,the more significant this difference becomes.An equivalent radius is introduced to fit and obtain a formula for calculating the peak overpressure and the shape factor of peak overpressure,which includes the aspect ratio as a variable,and a deviation between the calculated results and the numerically simulated results is less than 10%.

Key words: elliptical cross-section, shock wave, power characteristics, numerical simulation, prediction model

CLC Number:

O389

AN Chengyuan, LIU Haipeng, LIU Yan, REN Wei. Shock Wave Power Characteristics of Cylindrical Explosives with Elliptical Cross-section[J]. Acta Armamentarii, 2025, 46(8): 240969-.

Figures/Tables 26

Fig.1 Relative parameters of elliptical cross-section(left) and spatial position(right)

Table 1 Relative parameters of cylindrical explosives with elliptical variable-cross-section

参数	数值	参数	数值
ρ/(kg·m^-3)	1630	a/cm	4.67
M/g	1450	b/cm	3.33
H/cm	25	μ	1.4

Fig.2 Free-field static explosion experiment of cylindrical Explosives with elliptical cross-section

Fig.3 Numerical simulation model for the static airburst of explosives in an free field

Table 2 Parameters related to numerical simulation of explosives

ρ_e/(m·s^-3)	D_C-J(km·s^-1)	p_C-J/GPa	Q/(J·kg^-1)	A/GPa
1791	7.98	29.5	6487	524.2
B/GPa	R₁	R₂	ω	E₀
7.678	3.42	1.91	0.35	8.5

Fig 4 Typical overpressure-time curves obtained at characteristic locations through experiment and simulation

Fig.5 Typical overpressure-time curves obtained at characteristic locations through experiment and simulation

Table 3 Comparison of experimental and simulated peak overpressures

方向/(°)	距离/m	超压峰值/MPa		误差/%
方向/(°)	距离/m	实验值	数值模拟值	误差/%
0	1.5		0.434
	2.5	0.138	0.128	7.18
	3.5		0.063
45	1.5	0.735	0.760	3.40
	2.5	0.148	0.167	12.84
	3.5	0.080	0.071	11.25
90	1.5		1.438
	2.5	0.318	0.284	10.69
	3.5	0.091	0.097	6.59
135	1.5		0.760
	2.5	0.156	0.167	7.05
	3.5	0.084	0.071	14.46

Fig.6 The typical explosion images captured by ground-based high-speed cameras

Fig 7 Processed shock wave position image(left) and simulation image(right)

Fig.8 Shock wave front at 0° and 90° as a function of time

Fig.9 Shock wave front at z=50cm as a function of time

Fig.10 Images of far-field shock wave front during explosion

Fig.11 Shock wave front at z=150cm as a function of time

Fig 12 Overpressure-time curves at different azimuth angles at various distances

Fig 13 Impulse-time curves at different azimuth angles for distances of 2.5m and 3.0m

Fig.14 Comparison of shock wave wavefronts for cross-sectional and uniform cross-sectional cylindrical explosives with with variable and uniform cross-sections

Table 4 Relative parameters of TNT numerical simulation calculation

ρ/(kg·m^-3)	D/(km·s^-1)	p_C-J/GPa	Q/(J·kg^-1)	A/GPa
1630	6.9	21	4120	371.2
B/GPa	R₁	R₂	ω	E₀
3.21	4.15	0.95	0.3	7.0

Table 5 Geometric parameters of numerical simulation model

μ	a/cm	b/cm	μ	a/cm	b/cm
1.1	3.07	2.79	1.6	3.7	2.31
1.2	3.21	2.67	1.7	3.82	2.24
1.3	3.34	2.57	1.8	3.93	2.18
1.4	3.46	2.47	1.9	4.03	2.12
1.5	3.58	2.39	2.0	4.14	2.07

Fig.15 Spatial distribution of peak overpressure of shock wave

Fig.16 Spatial distribution of peak overpressure shape factor

Fig.17 Variation of peak overpressure shape factor with distance

Fig.18 The distribution of peak overpressure and its shape factor with respect to equivalent radius and scaled distance

Fig 19 Comparison of numerically simulated and calculated results

Fig.20 Comparation of computated results and simulated results

Fig.21 Comparation of experimental and computated results

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