## 1 Introduction
explored the relationship between the perforation behavior of unidirectional glass fiber-reinforced cross laminates and the shape of the projectile head, the impact angle, and the thickness of the laminates. [PERSON] et al. [30]. simulated the vertical and oblique impact behavior of a cylindrical cone-nosed projectile on a ductile target plate. The results show that the critical angle of the projectile's bounce increases with the increase in the projectile's impact velocity. The protrusions and holes are circular in the forward collision and elliptical in the oblique collision. [PERSON] et al. [31]. studied the high-speed oblique impact and residual tensile strength of quasi-isotropic carbon fiber/epoxy resin laminates. The results show that there is a strong correlation between the residual strength and the impact damage, which depends on the fiber fracture width and the size of the delamination area. A lot of research has also been carried out on the scenario of bird impact on aircraft. According to the contact collision coupling method, LS-DYNA was used to study the anti-bird impact performance of new materials and the finite element model of bird impact laminates was established. Preliminary bird impact analysis was carried out on the sandwich structure, and a small number of scholars studied the mechanical properties of various sandwich structures subjected to high-speed impact [32; 33]. The research on inclined impact sandwich plates has attracted more and more attention. The research involves the performance of SPS sandwich plates at different incident angles; the high-speed impact of the angle of attack on sandwich panels; the impact resistance of different impact angles, impact filling, and hollow honeycomb panels; the study on the oblique impact resistance of composite laminate skin foam aluminum sandwich structure under different impact angles; and the effect of impact angle on the impact resistance of aluminum honeycomb sandwich structure [34; 35; 36; 37; 38]. [PERSON] et al. [39]. simulated the structural response and failure mode of a honeycomb sandwich panel under the impact of a high-speed projectile and analyzed the influence of incident angle on the overall performance of the panel. Many scholars have carried out research on the low-speed impact resistance of honeycomb sandwich structures. However, after a large number of investigations of the literature, it was found that most scholars focus on the mechanical properties of the structure under positive impact conditions, and there are few studies on inclined impact conditions. Some studies involving inclined impact conditions are often only based on positive impact conditions. When the parameter influence analysis is carried out, the impact angle is discussed as a parameter, and the research lacks pertinence. In reality, there are very few cases that fully meet the positive impact. The impact of foreign objects on honeycomb sandwich structures often has a certain angle. The direct use of positive impact research conclusions to explain the widespread oblique impact events, in reality, is not sufficient. After the honeycomb sandwich structure is impacted by an external object, the specific damage mode is very complex. Coupled with the friction slip effect existing in the oblique impact, the damage and energy absorption become more complex. Impact events will certainly produce damage but are also inevitably accompanied by the transformation and transfer of energy. It is of great significance to explore the damage mechanism for improving the impact resistance of the structure. Similarly, when the structure is used as an energy absorption structure, energy absorption analysis can also help to improve its energy absorption efficiency.