## 1 Introduction  
With the development of military technology, armor protection for personnel is being increasingly emphasized. Body armor needs to resist the penetration of the bullet as well as absorb the energy of the bullet, preventing lethal damage to the personnel. Additionally, to effectively protect the person from auto weapons, multi-hit resistance is also required. Ceramics, compared to metals, have superior hardness, good strength, and low density, making them an attractive armor material. The ceramic armor plate has become an essential part of personal armor to protect from rifles or higher-level thread [1]. However, ceramics are brittle in nature with low toughness and are sensitive to defects [2]. Defects in the ceramics can facilitate crack propagation and effectively reduce the ballistic performance of the ceramics [3]. The defects are often introduced to the ceramic green body during fabrication and are not eliminated during sintering. The ceramics prepared by colloid processing have fewer defects in the final products compared to the ceramics made by the conventional dry-pressing route [4]. Laminated ceramics, which are prepared by stacking ceramic green tapes and sintering, allow for fabrication from colloid processing [5, 6] and would be advantageous over conventional dry-pressed ceramics in armor application. The introduction of the weak interface layer to the laminated ceramics has also been proven to be effective in toughening the ceramics and thus enhancing the energy absorption of the ceramics. The toughening mechanism of the laminated ceramics was proposed by [PERSON] [7] in 1964 in that crack deflection would occur by introducing the weak interface in the composite. In 1990, [PERSON] [8] first prepared the SiC/C laminated composite using this strategy and reported that the material had several times higher toughness and 100 times higher work of fracture than that of the bulk SiC. Since then, many studies have been carried out on laminated ceramics to develop high toughness in ceramics. The layer-by-layer stacking method provided laminated ceramics many design variables, such as the layer composition, layer thickness, stacking sequence for layers with different compositions, etc. The effects of these designing factors were extensively studied to optimize mechanical performance. The strength of the matrix layer was found to be important to the final mechanical properties of the laminated ceramics [9]. Toughening the matrix layer of the laminated ceramics would provide more percentage of improvement to the overall toughness than toughening the monolithic ceramics [10]. An optimal range of the bonding strength of the interface layer also exists in which the toughness of the laminated ceramics reaches the maximum [6; 10]. However, it is still in doubt whether the toughening mechanism of the layered ceramics for static mechanical loading is effective for the ballistic impact. The ballistic impact is a complex dynamic event that is very different from static mechanical loading [11]. Due to the difficulty in theoretical study and analysis, no conclusion has been drawn until now. The study for the ballistic performance of laminated ceramics has been very limited. The only study, carried out by [PERSON] et al. [12], reported that the laminated Si\({}_{3}\)N\({}_{4}\)/BN would remain a whole piece after ballistic impact, while the monolithic Si\({}_{3}\)N\({}_{4}\) broke into pieces, but the penetration resistance of the laminated ceramics was decreased. Introducing the weak interface layer only at the backside of the ceramic plate would mitigate the penetration resistance decrease. The laminating structure is an important factor in the performance of laminated ceramics. Previous studies in the AlN/polymer laminated composite found that the composite would have a depth of penetration (DOP) greater or less than the monolithic AlN, depending on the layer structure [13; 14]. However, such an effect on ballistic performance has not been studied for laminated ceramics.