多点同时爆炸对钢筋混凝土方柱构件的毁伤特性

To investigate the influence of damage characteristics, dynamic response, and failure mechanism on reinforced concrete (RC) square columns under multi-point simultaneous initiation, a series of experiments were conducted on RC square columns subjected to synchronous contact explosive loading using single, double, and four-point charges. Furthermore, LS-DYNA was used to analyze the damage characteristics and stress evolution process based on the experimental results obtained from the explosive loading. The analysis results indicate that the damage effect of RC square columns relies on both the number of detonation points and the placement position, given the same total mass of explosives. Multi-point simultaneous initiation causes superior damage to RC square columns with both crushed and punched damage, as compared to single-point explosions. Additionally, the degree of damage and acceleration response of the RC square columns is the highest at the condition of four-point charges on adjacent sides. The effectiveness of enhancing the damaging effect on RC square columns is directly correlated with the increase in the number of detonation points. The RC square column initially enters a high-stress state throughout the entire section, and in the condition of four-point charges placed on all four sides, there are four corners where the concrete stress is concentrated, leading to enhanced damage effects. During single-point initiation, the stress inside the concrete at the measuring point decreases as the distance from the center of the explosion increases. However, during multipoint initiation, when multiple explosion stress waves are combined within the cross-section of the RC square column, the stress at the central concrete significantly increases. Taking into account the spatial coupling and superposition of stress waves, the concrete's peak stress at the center of the RC square column section increased significantly under the explosive conditions of four-point charges on adjacent sides. Specifically, the peak stress reached 37.3 MPa, with stress increases of 3.82 times, 1.21 times, and 0.67 times compared to the other three explosion conditions. The increase in stress coupling is the primary factor contributing to the extensive damage observed in the RC square column.