13.3 Field Blast Test
439
Fig. 13.3 Charge placement (unit mm)
0.5 ~ 1.0 m/kg
1/3 . As shown in Fig. 13.3, all the cylindrical charges were positioned
horizontally with their symmetry axis parallel to the concrete panel and perpendicular
to its shorter axis of symmetry, which was initiated at one end by using an electrical
detonator.
13.3.3 Test Results and Discussions
In this section, the explosion-induced instantaneous incident and reflected overpressures are assessed firstly, and the influences of scaled distance, charge shape and point
of detonation are discussed. Then, the deflection- and acceleration-time histories as
well as post-blast damage of two typical panels with different scaled distances are
analyzed and compared.
13.3.3.1 Overpressure-Time History
Figure 13.4 shows the recorded incident overpressure curves, in which the data
from IP1, IP2, and IP3 are denoted as P i1 , P i2 , and P i3 , respectively. The reliability of incident overpressure curves was proved by the good repeatability between
the curves observed from different shots. The averaged peak values, time durations
and impulses of the incident and reflected blast wave overpressures are listed in
Table 13.3. It can be found that, the average peak overpressures of P i1 , P i2, and P i3
are 0.071 MPa, 0.058 MPa, and 0.034 MPa, and the corresponding average impulses
are 0.090 MPa•ms, 0.088 MPa•ms, and 0.063 MPa•ms, respectively. The peak overpressure and overpressure-time histories resulting from the detonation of a cylindrical
charge are dependent on the aspect ratio (length/diameter) of the cylinder, which is
3.73 in the present test from Fig. 13.3. The peak pressure of P i1 is significantly larger
than that of P i2 , although they were measured with close scaled distances, i.e., 3.055
439
Fig. 13.3 Charge placement (unit mm)
0.5 ~ 1.0 m/kg
1/3 . As shown in Fig. 13.3, all the cylindrical charges were positioned
horizontally with their symmetry axis parallel to the concrete panel and perpendicular
to its shorter axis of symmetry, which was initiated at one end by using an electrical
detonator.
13.3.3 Test Results and Discussions
In this section, the explosion-induced instantaneous incident and reflected overpressures are assessed firstly, and the influences of scaled distance, charge shape and point
of detonation are discussed. Then, the deflection- and acceleration-time histories as
well as post-blast damage of two typical panels with different scaled distances are
analyzed and compared.
13.3.3.1 Overpressure-Time History
Figure 13.4 shows the recorded incident overpressure curves, in which the data
from IP1, IP2, and IP3 are denoted as P i1 , P i2 , and P i3 , respectively. The reliability of incident overpressure curves was proved by the good repeatability between
the curves observed from different shots. The averaged peak values, time durations
and impulses of the incident and reflected blast wave overpressures are listed in
Table 13.3. It can be found that, the average peak overpressures of P i1 , P i2, and P i3
are 0.071 MPa, 0.058 MPa, and 0.034 MPa, and the corresponding average impulses
are 0.090 MPa•ms, 0.088 MPa•ms, and 0.063 MPa•ms, respectively. The peak overpressure and overpressure-time histories resulting from the detonation of a cylindrical
charge are dependent on the aspect ratio (length/diameter) of the cylinder, which is
3.73 in the present test from Fig. 13.3. The peak pressure of P i1 is significantly larger
than that of P i2 , although they were measured with close scaled distances, i.e., 3.055