## 1 Introduction
Due to its unique molecular structure, the chemical reaction of polyurea elastomer is essentially the interaction between semi-prepolymers, amino polyether, and amine chain extenders. By adjusting the chain extenders and other reactants, the mechanical properties of polyurea elastomers can be enhanced. Moreover, the cleavage of hydrogen bonds within the hard segments of the microstructure allows for partial energy absorption, which contributes to its excellent mechanical properties and energy-dissipation mechanism. These characteristics provide a solid foundation for the study of polyurea elastomer's response to explosive impact. Polyurea elastomers have garnered significant attention from numerous experts and scholars for their exceptional performance in enhancing the blast and penetration resistance of structures [5; 6; 7; 8; 9; 10]. In 1996, the Air Force Research Laboratory (AFRL) first selected polyurea from 21 elastomeric materials as an impact-resistant protective coating [11; 12]. Regarding masonry structures, [PERSON] [13] conducted a simulation analysis on polyurea-coated masonry walls. By comparing the damage to the central section of walls with and without polyurea coating under a 50 kg TNT explosion, it was found that uncoated masonry experienced severe damage with substantial fragmentation, while the polyurea-coated masonry showed significantly less damage with almost no debris ejection, indicating that polyurea can enhance the blast resistance of masonry structures. [PERSON] et al. [14] explored the blast resistance of masonry walls reinforced with various methods, including fiber-reinforced composites, galvanized steel sheets, and polyurea elastomer coatings. The results of their blast tests demonstrated that walls reinforced with polyurea coatings maintained better structural integrity and effectively contained debris within the structure. For steel structures, [PERSON] [7] investigated the impact of polyurea coatings on the failure of steel plates under explosive loads. Their experimental results revealed that steel plates with polyurea coatings exhibited greater residual deformation, with the degree of deformation increasing as the coating thickness increased. [PERSON] [15] conducted a simulation analysis on the dynamic response and deformation of circular steel plates with and without polyurea coatings. Their findings showed that polyurea-coated steel plates exhibited superior blast resistance compared to uncoated plates. Notably, plates coated with polyurea on the back side of the blast showed better blast resistance than those coated on the front side or without any coating. Additionally, the difference in blast resistance became more pronounced with increasing polyurea coating thickness. A substantial body of research has been conducted by both domestic and international scholars on the blast damage behavior of bridge structures. In the field of concrete box girders, [PERSON] [16] employed ANSYS/LS-DYNA software ([[https://www.lstc.com/products/ls-dyna](https://www.lstc.com/products/ls-dyna)]([https://www.lstc.com/products/ls-dyna](https://www.lstc.com/products/ls-dyna))) to analyze the damage response of a three-tower, double-cable, self-anchored suspension bridge subjected to varying explosive charges and detonation heights. The study identified the minimum charge necessary to cause damage under different conditions. [PERSON] [17] examined the failure behaviors of reinforced concrete box girders through both blast experiments and numerical simulations. [PERSON] [18] utilized ANSYS/LS-DYNA software to investigate the dynamic behavior and failure modes of prestressed concrete box girders under different TNT charge amounts, blast positions, and levels of prestress loss. [PERSON] et al. [19], [PERSON] et al. [20], [PERSON] [21], [PERSON] [22], and [PERSON] [23] conducted multiple experimental investigations focused on the blast effects on bridge pier components.