In this paper, oblique crushing behaviors of the hierarchical hexagonal steel tubes were investigated. In the oblique impact, the crushing mode transfers from axial crushing dominated mode to bending dominated mode with the increase of the impact angle. In normal impact, the hierarchical steel tubes have progressive folding and global folding, depending on the cell number and the thickness of the sandwich wall. There are two hybrid crushing modes at oblique impact, progressive-folding-bending (hybrid mode II) and global-folding-bending (hybrid mode III). Before the hybrid crushing mode appears, the peak force is reduced but the energy absorbing performance changes little compared with the normal impact. When the impact angle is 10°, the hierarchical steel tube still has excellent energy absorption. It is also found that when the cell number in the sandwich wall changes from 4 to 6, the crushing mode at the impact angle of 10° transfers from progressive folding, hybrid folding II to hybrid folding III, while the crushing mode at normal impact transforms from progressive folding, hybrid folding I to global folding. It is found that adopting hierarchical topology can greatly improve the energy absorption at oblique impact, even better than that of the normally impacted single-cell tubes.

本文研究了分层六角形钢管的斜向破碎行为。在倾斜冲击中，随着冲击角的增加，破碎模式从轴向破碎模式转变为弯曲模式。在正常的冲击下，分层的钢管具有渐进式折叠和整体式折叠，这取决于夹层壁的格数和厚度。在倾斜冲击下有两种混合破碎方式：渐进式弯曲弯曲（混合模式II）和整体折叠弯曲（混合模式III）。在混合破碎模式出现之前，峰值力减小了，但能量吸收性能与正常冲击相比变化不大。当冲击角为10°时，分级钢管仍具有优异的能量吸收。还发现，当夹心壁中的单元数从4变为6时，在10°冲击角下的破碎模式从渐进折叠，混合折叠II转变为混合折叠III，而在正常冲击下的破碎模式转变从渐进式折叠，混合式折叠I到整体折叠。结果发现，采用分层拓扑结构可以大大提高倾斜冲击时的能量吸收，甚至比正常冲击的单细胞管更好。