This paper investigates the damaged area of a reinforced concrete beam under rectangular explosive contact explosion, through full-scale beam tests and numerical simulation. The calculation equation of beam surface load distribution based on equivalent impulse is established, with a consideration of the effect of the length and height of rectangular explosive on the load distribution, and the calculation equation of beam damage area is further proposed. Through changing the mass of the rectangular TNT explosive (1~6 kg) and the shape of the 1 kg rectangular explosive, 5 cases of the test were carried out on a full-scale reinforced concrete beam. The damaged area of the beam is divided into three parts: blasting crater, damage span of the front face, and damage span of the bottom face. The RHT (Riedel–Hiermaier–Thoma) material model is used to simulate concrete for numerical simulation. Curve fitting was performed based on the numerical simulation results. With the prediction of the load distribution on the beam surface, the size of the surface crushing area and the span of the damaged area are calculated; the section resistance function of the beam is introduced to calculate the depth of the blasting crater; and the correlation curve between the damaged span of the front face, the depth of the blasting crater, and the mass of the block TNT is established. The local damage to the beam under the contact explosion load can be evaluated more accurately when the mass of the rectangular TNT is 1~6 kg.

How to effectively reduce the damage of frequent accidental explosions and explosion attacks to existing walls is an important concern of the blast resistance field. In the present study, the influence of the foamed concrete (density 820 kg/m³, water-cement ratio 0.4) coating thickness on the blast resistance of a 120 mm RC (reinforced concrete) wall was studied through blast experiments, numerical simulations, and shock wave theory. Results show that the influences of foamed concrete on the blast resistance of RC walls are jointly decided by the stress drop caused by impedance effect and exponential attenuation and the stress rise caused by high-speed impact compression. The coating thickness mainly affects the foam concrete’s fragmentation degree and stress attenuation. A lower critical coating thickness exists in foamed concrete-coated RC walls. The blast resistance of the RC wall will decrease when the coating thickness is less than that value. The lower critical coating thickness is related to the intensity of blast load and the energy absorption capacity of foamed concrete, and it can be predicted by monitoring the explosive stress and energy incident to the RC wall.

The formation characteristics of the shaped charge jet (SCJ) from the shaped charge with a trapezoid cross-section is analyzed in this work. A theoretical model was developed to analyze the collapsing mechanism of the liner driven by the charge with a trapezoid cross-section. Based on the theoretical model, the axial and radial velocities of the SCJ from different trapezoid cross-section charges. The pressure model was employed to calculate the velocity for the subcaliber shaped charge, which was verified through numerical simulation. The results show that the influence of the angle of the trapezoidal charge (acute angle) on the axial velocity of the SCJ is not distinct, whereas the variation of the radial velocity of the shaped charge jet is obvious as the change in the angle of the trapezoidal charge. In addition, the related X-ray experiments were conducted to verify the theory. The theoretical results correlate with the experimental results reasonably well.