From the macro- to the nanoscale, kirigami structures show novel and tunable properties by tailoring the original two-dimensional sheets. In this study, the large stretchability and failure behavior in graphene nanoribbon kirigami (GNR-k) are obtained using the finite element (FE) method and molecular dynamics (MD) simulations. The carbon–carbon bond in the FE method is equivalent to a nonlinear Timoshenko beam based on the Tersoff-Brenner potential. All the results from the present FE method are in reasonable agreement with those from our MD simulations using the REBO potential. These results from the two methods show that the maximum ultimate strain of GNR-k (around 100%) is around 4 times higher than that of a pristine graphene nanoribbon (GNR), whereas the minimum ultimate stress of GNR-k is around one order of magnitude lower than that of the GNR. In particular, the large stretchability of GNR-k is indirectly proven to be mainly derived from the out-of-plane bending deformation by measuring the nonlinear mechanical properties of paper kirigami. Our results provide physical insights into the origins of the large stretchability of GNR-k and make GNR-k applicable to flexible nanodevices.

中文翻译：

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拉伸状态下石墨烯基拉米的大拉伸性和破坏机理

从宏观到纳米，折纸结构通过剪裁原始的二维片材而显示出新颖且可调的特性。在这项研究中，使用有限元（FE）方法和分子动力学（MD）模拟获得了石墨烯纳米带kirigami（GNR-k）中的较大拉伸性和破坏行为。有限元方法中的碳-碳键相当于基于Tersoff-Brenner势的非线性Timoshenko束。当前有限元方法的所有结果与我们使用REBO势的MD模拟得出的结果基本吻合。这两种方法的结果表明，GNR-k的最大极限应变（约100％）是原始石墨烯纳米带（GNR）的约4倍，而GNR-k的最小极限应力比GNR-k低约一个数量级。特别是，通过测量纸千纸鹤的非线性机械性能，间接证明了GNR-k的大拉伸性主要源自平面外弯曲变形。我们的结果提供了对GNR-k大可拉伸性起源的物理见解，并使GNR-k适用于柔性纳米器件。