Fracturing of topological Maxwell lattices
Fracturing of topological Maxwell lattices
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DOI：
10.1088/1367-2630/aac765
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发表时间：
2018-01
影响因子：
3.3
通讯作者：
Leyou Zhang;Xiaoming Mao
中科院分区：
文献类型：
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作者：
Leyou Zhang;Xiaoming Mao
本文给出了拓扑麦克斯韦晶格在外加应力作用下的断裂分析。麦克斯韦晶格是在体中包含相等数量的自由度和约束的机械结构，因此处于机械不稳定性的边缘。拓扑力学的最新进展导致在麦克斯韦晶格的边缘和畴壁处发现了拓扑保护的松弛模和自应力态。当正常的脆性材料被拉伸时，应力集中在裂纹尖端，导致灾难性的破坏。相反，我们发现当拓扑麦克斯韦晶格被拉伸时，应力集中在自应力畴壁的状态上，并且键断裂事件从这些畴壁开始，即使存在裂纹。值得注意的是，我们发现自应力畴壁的应力集中特征持续到破坏过程的深处，当大量的损伤已经发生在这些畴壁。我们用拓扑力学理论解释了这些结果，并讨论了这些拓扑麦克斯韦晶格结构作为机械超材料的潜在用途，表现出高强度的抗断裂和良好的控制断裂过程。
We present fracturing analysis of topological Maxwell lattices when they are stretched by applied stress. Maxwell lattices are mechanical structures containing equal numbers of degrees of freedom and constraints in the bulk and are thus on the verge of mechanical instability. Recent progress in topological mechanics led to the discovery of topologically protected floppy modes and states of self stress at edges and domain walls of Maxwell lattices. When normal brittle materials are being stretched, stress focuses on crack tips, leading to catastrophic failure. In contrast, we find that when topological Maxwell lattices are being stretched, stress focuses on states of self stress domain walls instead, and bond-breaking events start at these domain walls, even in presence of cracks. Remarkably, we find that the stress-focusing feature of the self-stress domain walls persists deep into the the failure process, when a lot of damages already occurred at these domain walls. We explain the results using topological mechanics theory and discuss the potential use of these topological Maxwell lattice structures as mechanical metamaterials that exhibit high strength against fracturing and well controlled fracturing process.