432
13 Experimental and Numerical Studies on Dynamic Behavior …
weight of the equivalent TNT explosive) as the close-, medium- and far-range explosion scenarios, respectively. Most of the existing work is either concerning the local
damage and failure of UHPCC panels under contact/close-in explosions or focusing
on the dynamic performance of UHPCC panels under far-range explosions, the
related studies for the medium-range explosions are insufficient; (ii) For the design of
test setup, the existing test UHPCC panels were usually constrained by a ground frame
which is completely exposed to air and could not eliminate the effect of the diffracted
blast waves on the rear face of test panel. The boundary conditions of the test panel
provided by the steel angles and wood stripes are not clear. Besides, attributed to
the damage of the measuring sensors under intensive blast loadings, the systematic
dynamic responses of panels, e.g. deflection- and acceleration-time histories, as well
as the instantaneous incident and reflected blast overpressures are limited; (iii) K&C
model (Malvar et al. 1997) (*MAT_CONCRETE_DAMAGE_REL3, *MAT_72R3)
embedded in LS-DYNA (LSTC 2007) is validated for capturing the complex concrete
behaviors and predicting the structural dynamic responses under blast loadings with
good accuracy (Jayasooriya et al. 2014; Wu et al. 2011; Zhang and Jin 2012). The
most significant user improvement provided by *MAT_72R3 is the model parameters auto-generated algorithm based solely on the unconfined compression strength
of concrete. However, this parameter generation algorithm is proposed for NSC with
the uniaxial compressive strength of 45 MPa. Therefore, the corresponding K&C
constitutive model parameters for UHPCC should be comprehensively calibrated,
while the related work is very lacked.
At present, in Sect. 13.3, three reinforced UHPCC panels and three NSC control
panels were fabricated and tested on a specially designed box-like blast loading
apparatus to avoid the effect of the diffracted blast waves and provide the simplysupported boundary constraints, and the scaled distances of 4 kg TNT charges were
ranged from 0.5 to 1.0 m/kg
1/3 . Various sensors were arranged to record the incident
and reflected overpressure-time histories, deflection-and acceleration-time histories.
Besides, by examining the damage of the post-blast panels, the blast resistance of
NSC and UHPCC panels are evaluated quantitatively. Then, in Sect. 13.4, the refined
FE models of the present test was established, and the parameters of K&C model for
UHPCC are comprehensively calibrated. Finally, in Sect. 13.5, the applicability of
the CONWEP method to predict the blast overpressures are firstly discussed, and then
the simulated dynamic responses and damage of panels are compared systematically
with the test results. The present conclusions can provide references in the design
and analyses of UHPCC protective structures under blast loadings.
13.2 Review of the Existing Work
As for the existing experimental studies, Li et al. (2016) carried out the contact
explosion test on seven reinforced NSC and UHPC slabs with the scaled distance Z
of 0.043 m/kg
1/3 and 0.06 m/kg
1/3 , respectively. The slabs with the dimensions of 2 m
length, 0.8 m width, and 0.1–0.15 m thickness were tested on a steel frame provided
13 Experimental and Numerical Studies on Dynamic Behavior …
weight of the equivalent TNT explosive) as the close-, medium- and far-range explosion scenarios, respectively. Most of the existing work is either concerning the local
damage and failure of UHPCC panels under contact/close-in explosions or focusing
on the dynamic performance of UHPCC panels under far-range explosions, the
related studies for the medium-range explosions are insufficient; (ii) For the design of
test setup, the existing test UHPCC panels were usually constrained by a ground frame
which is completely exposed to air and could not eliminate the effect of the diffracted
blast waves on the rear face of test panel. The boundary conditions of the test panel
provided by the steel angles and wood stripes are not clear. Besides, attributed to
the damage of the measuring sensors under intensive blast loadings, the systematic
dynamic responses of panels, e.g. deflection- and acceleration-time histories, as well
as the instantaneous incident and reflected blast overpressures are limited; (iii) K&C
model (Malvar et al. 1997) (*MAT_CONCRETE_DAMAGE_REL3, *MAT_72R3)
embedded in LS-DYNA (LSTC 2007) is validated for capturing the complex concrete
behaviors and predicting the structural dynamic responses under blast loadings with
good accuracy (Jayasooriya et al. 2014; Wu et al. 2011; Zhang and Jin 2012). The
most significant user improvement provided by *MAT_72R3 is the model parameters auto-generated algorithm based solely on the unconfined compression strength
of concrete. However, this parameter generation algorithm is proposed for NSC with
the uniaxial compressive strength of 45 MPa. Therefore, the corresponding K&C
constitutive model parameters for UHPCC should be comprehensively calibrated,
while the related work is very lacked.
At present, in Sect. 13.3, three reinforced UHPCC panels and three NSC control
panels were fabricated and tested on a specially designed box-like blast loading
apparatus to avoid the effect of the diffracted blast waves and provide the simplysupported boundary constraints, and the scaled distances of 4 kg TNT charges were
ranged from 0.5 to 1.0 m/kg
1/3 . Various sensors were arranged to record the incident
and reflected overpressure-time histories, deflection-and acceleration-time histories.
Besides, by examining the damage of the post-blast panels, the blast resistance of
NSC and UHPCC panels are evaluated quantitatively. Then, in Sect. 13.4, the refined
FE models of the present test was established, and the parameters of K&C model for
UHPCC are comprehensively calibrated. Finally, in Sect. 13.5, the applicability of
the CONWEP method to predict the blast overpressures are firstly discussed, and then
the simulated dynamic responses and damage of panels are compared systematically
with the test results. The present conclusions can provide references in the design
and analyses of UHPCC protective structures under blast loadings.
13.2 Review of the Existing Work
As for the existing experimental studies, Li et al. (2016) carried out the contact
explosion test on seven reinforced NSC and UHPC slabs with the scaled distance Z
of 0.043 m/kg
1/3 and 0.06 m/kg
1/3 , respectively. The slabs with the dimensions of 2 m
length, 0.8 m width, and 0.1–0.15 m thickness were tested on a steel frame provided