###### Abstract  
In this paper, the AUTODYN/Smoothed Particle Hydrodynamics (SPH) method was used to study the impact of reactive fragments on three-layer equidistant steel plates. The perforation characteristics of equidistant three-layer steel plates were investigated along with the parameters of combustion energy release from reactive fragments under varied impact velocities and shape conditions. The modification of the steel plates' perforation diameter was investigated using the dimensional analysis approach. The shock wave pressure and chemical reaction characteristics were examined using the shock wave theory. The results show that within the examined impact velocity range, the perforation diameter initially increased and then decreased as the impact velocity of the reactive fragment rose. In addition, the perforation diameter was approximately 1.5-3 times the diameter of the reactive fragment. As the impact speed increased  
reactive fragments are structural materials that show properties that facilitate ignition during impact [13; 14; 15]. It will be interesting to observe what kind of perforation the three layers of uniformly spaced steel plate will undergo when reactive fragments impact them [16; 17]. The perforation diameter of steel plates under impact conditions serves as a reference criterion for quickly estimating the damage characteristics of steel plates. As a result, the perforation diameter of steel plates under impact conditions has drawn the interest of numerous academics, making it a disputed and significant topic in modern research [18; 19; 20]. For the diameter of impact perforation, researchers have used semi-empirical and empirical formulations [21; 22; 23]. Researchers have created empirical or semi-empirical models to depict the variables that affect the perforation diameter brought on by the impact of inert bullets on steel plates [24; 25; 26]. However, there are few studies on semi-empirical formulations for the perforation diameter under the impact conditions of reactive fragments. In this case, it is crucial to develop a quick empirical formula for estimating the perforation diameter. The Lagrange grid method is prone to mesh failure when simulating large deformations under high-speed impacts; when simulating large deformations under hypervelocity impacts, Euler grids are prone to the problem of empty grids [27]. Therefore, these two grid methods have certain limitations. The SPH method [28; 29; 30] is a meshless numerical simulation computation approach that can prevent the Lagrange mesh method's mesh distortion failure in the case of significant deformation. In addition, the SPH method [31; 32; 33] can avoid the problems of empty grids that arise in simulating hypervelocity impacts. In the case of a hypervelocity impact, it is better suited for modeling the performance of the material response. As a result, the SPH approach can more accurately mimic the behavior of materials under hypervelocity impacts. The response of steel plates to impact damage depends on a variety of parameters, such as the impact velocity, steel plate types, shape of the reactive fragments, thickness, distance between the steel plates, and other factors [5; 11; 34]. AUTODYN has a distinct advantage in simulating hypervelocity impacts [35; 36]. This paper focuses on the numerical simulation study of equal mass and volume of cylindrical and spherical reactive fragments impacting Q345S (Q345 steel) or 304 SS (304 stainless steel) plates with different velocities by using the numerical simulation AUTODYN. This study, which is highly innovative, used the quantitative analysis method to thoroughly analyze the impact of speed, kinetic energy, and chemical energy effects on the perforation. Additionally, this will offer techniques and suggestions for achieving a more precise fitting of perforation diameter formulas in subsequent studies. Impact experiments validated the numerical simulation results in this paper and have a certain rationality.