Steel-tube-confined concrete (STCC) targets are provided with excellent anti-penetration performance over semi-infinite concrete (SIC) targets since the steel tube imposes passive restraint on the in-filled concrete during the penetration process. Grid STCC system with square steel tubes is a potential solution to protective structures. In this paper, experiments of 9-cell grid STCC targets penetrated by 12.7 mm Armor Piercing Projectile (APP) were performed. The influence of side length and thickness of steel tube, steel ratio and impact velocity on anti-penetration performance were taken into account. Additionally, single-cell square STCC targets were also designed and tested for comparison with the 9-cell grid STCC targets. Damage modes and parameters of the tested targets were measured and discussed. Moreover, the stiffness of radial confinement of grid STCC targets is achieved according to the elastic solution of infinite cylindrical shell in Winkler medium. Furthermore, the penetration resistance and depth of penetration (DOP) for grid STCC targets are obtained on the basis of the dynamic finite spherical cavity-expansion (FSCE) models including radial confinement effect. It is shown that the 9-cell grid STCC targets with optimal dimension match of thickness and side length of steel tube can reduce the DOP by about 17 % and 23 % in comparison with the SIC targets and single-cell square STCC targets, respectively, due to both the confinement of square steel tube to concrete in the impacted cell and the additional confinement of the surrounding cells to the impacted cell; the penetration resistance and DOP of the grid and cellular STCC targets with similar steel ratio is close, and thus the grid STCC targets with simpler manufacturing process and excellent in-plane expandability are preferred in engineering practice; moreover, the predicted results of DOP model based on the FSCE models agree well with the tested results with the maximum disparity less than 12 % and the proposed model is more applicable to the grid and cellular STCC targets with high radial confinement.

钢管约束混凝土 (STCC) 靶材比半无限混凝土 (SIC) 靶材具有出色的抗渗透性能，因为钢管在渗透过程中对填充混凝土施加了被动约束。带有方钢管的网格 STCC 系统是保护结构的潜在解决方案。在本文中，进行了 12.7 毫米穿甲弹（APP）穿透 9 单元格 STCC 目标的实验。考虑了钢管的边长和壁厚、钢比和冲击速度对抗穿透性能的影响。此外，还设计并测试了单细胞方形 STCC 目标，以与 9 细胞网格 STCC 目标进行比较。对测试目标的损伤模式和参数进行了测量和讨论。而且，根据无限圆柱壳在Winkler介质中的弹性解，求得网格STCC靶的径向约束刚度。此外，基于包含径向约束效应的动态有限球腔膨胀（FSCE）模型，获得了网格STCC靶材的穿透阻力和穿透深度（DOP）。结果表明，与 SIC 靶材和单胞方形 STCC 靶材相比，具有最佳钢管厚度和边长尺寸匹配的 9 单元格 STCC 靶材的 DOP 分别降低了约 17 % 和 23 %，由于方钢管对受影响单元中混凝土的限制，以及周围单元对受影响单元的额外限制；具有相似钢比的网格和蜂窝STCC靶材的抗穿透性和DOP接近，因此工程实践中优选制造工艺更简单、面内扩展性好的网格STCC靶材；此外，基于FSCE模型的DOP模型预测结果与测试结果吻合较好，最大差异小于12%，该模型更适用于径向约束较高的网格和蜂窝STCC目标。