Mechanical performance of 3d-printed polyamide sandwich beams with different type of the lattice cores is investigated. Four variants of the beams are considered, which differ in the type of connections between the elements in the lattice structure of the core. We consider the pantographic-type lattices formed by the two families of inclined beams placed with small offset and connected by stiff joints (variant 1), by hinges (variant 2) and made without joints (variant 3). The fourth type of the core has the standard plane geometry formed by the intersected beams lying in the same plane (variant 4). Experimental tests were performed for the localized indentation loading according to the three-point bending scheme with small span-to-thickness ratio. From the experiments we found that the plane geometry of variant 4 has the highest rigidity and the highest load bearing capacity in the static tests. However, other three variants of the pantographic-type cores (1–3) demonstrate the better performance under the impact loading. The impact strength of such structures are in 3.5–5 times higher than those one of variant 4 with almost the same mass per unit length. This result is validated by using numerical simulations and explained by the decrease of the stress concentration and the stress state triaxiality and also by the delocalization effects that arise in the pantographic-type cores.

研究了具有不同类型晶格芯的 3d 打印聚酰胺夹层梁的机械性能。考虑了梁的四种变体，它们的不同在于核心的晶格结构中的元素之间的连接类型。我们考虑由两个倾斜梁族以小偏移放置并通过刚性接头（变体 1）、铰链（变体 2）和无接头（变体 3）连接而形成的缩放型格子。第四种类型的核心具有由位于同一平面上的交叉梁形成的标准平面几何形状（变体 4）。根据具有小跨厚比的三点弯曲方案对局部压痕加载进行了实验测试。从实验中我们发现，在静态测试中，变体4的平面几何具有最高的刚度和最高的承载能力。然而，缩放型芯的其他三种变体 (1-3) 在冲击载荷下表现出更好的性能。这种结构的冲击强度比几乎相同的单位长度质量的变体 4 的冲击强度高 3.5-5 倍。该结果通过使用数值模拟得到验证，并通过应力集中和应力状态三轴性的降低以及缩放型岩心中出现的离域效应来解释。这种结构的冲击强度比几乎相同的单位长度质量的变体 4 的冲击强度高 3.5-5 倍。该结果通过使用数值模拟得到验证，并通过应力集中和应力状态三轴性的降低以及缩放型岩心中出现的离域效应来解释。这种结构的冲击强度比几乎相同的单位长度质量的变体 4 的冲击强度高 3.5-5 倍。该结果通过使用数值模拟得到验证，并通过应力集中和应力状态三轴性的降低以及缩放型岩心中出现的离域效应来解释。