Vertically aligned carbon nanotube (VACNT) arrays or “forests” represent a promising class of mechanically strong and resilient lightweight materials, capable of supporting large reversible deformation and absorbing mechanical energy. The mechanical response of VACNT forests to uniaxial compression is defined by various factors, including the material microstructure, its density, height, rate of deformation, and the nature of interaction between carbon nanotubes (CNTs) and the compressing indenter. In this paper, we use a coarse-grained mesoscopic model to simulate the uniaxial compression of VACNT samples with different densities and microstructures (bundle size distribution and degree of nanotube alignment) to obtain a clear microscopic picture of the structural changes in networks of interconnected CNT bundles undergoing mechanical deformation. The key factors responsible for the coordinated buckling of CNTs, reversible and irreversible modes of deformation for VACNTs undergoing uniaxial compression, as well as hysteresis behavior in VACNT arrays subjected to five loading–unloading cycles are investigated in the simulations. The simulation results reveal the important role of the collective buckling of CNTs across bundle cross-sections as well as a complex deformation behavior of VACNT arrays defined by an interplay of different modes of bundle deformation. The loading rate and the CNT attachment to the indenter are found to have a strong effect on the deformation mechanisms and the overall mechanical behavior of VACNT forests. A good agreement with experimental data from in situ mechanical tests is observed for general trends and magnitudes of loss coefficients predicted in the simulations. The forest morphology can strongly alter the mechanical behavior of VACNT arrays with nominally the same general characteristics, such as CNT radius, length, and material density, thus suggesting the opportunity for substantial enhancement of the mechanical properties through the microstructure modification.

垂直排列的碳纳米管（VACNT）阵列或“森林”代表了有希望的一类具有机械强度和弹性的轻质材料，能够支持大的可逆变形并吸收机械能。VACNT林对单轴压缩的机械响应由各种因素定义，包括材料的微观结构，密度，高度，变形率以及碳纳米管（CNT）与压缩压头之间相互作用的性质。在本文中，我们使用粗粒度介观模型来模拟具有不同密度和微观结构（束尺寸分布和纳米管排列程度）的VACNT样品的单轴压缩，以获得互连的CNT网络中结构变化的清晰微观图像。束经受机械变形。在模拟中研究了碳纳米管的协调屈曲，承受单轴压缩的VACNTs的可逆和不可逆变形模式以及在VACNT阵列中经受五个加载-卸载循环的滞后行为的关键因素。仿真结果揭示了碳纳米管在束横截面上的整体屈曲的重要作用，以及由束不同变形模式的相互作用所定义的VACNT阵列的复杂变形行为。发现加载速率和CNT附着在压头上对VACNT林的变形机制和整体机械性能有很大影响。与来自 在模拟中研究了经受单轴压缩的VACNTs的可逆和不可逆变形模式，以及在VACNT阵列中经受五个加载-卸载循环的滞后行为。仿真结果揭示了碳纳米管在束横截面上的整体屈曲的重要作用，以及由束不同变形模式的相互作用所定义的VACNT阵列的复杂变形行为。发现加载速率和CNT附着在压头上对VACNT林的变形机制和整体机械性能有很大影响。与来自 在模拟中研究了经受单轴压缩的VACNTs的可逆和不可逆变形模式，以及在VACNT阵列中经受五个加载-卸载循环的滞后行为。仿真结果揭示了碳纳米管在束横截面上的整体屈曲的重要作用，以及由束不同变形模式的相互作用所定义的VACNT阵列的复杂变形行为。发现加载速率和CNT附着在压头上对VACNT林的变形机制和整体机械性能有很大影响。与来自 仿真结果揭示了碳纳米管在束横截面上的整体屈曲的重要作用，以及由束不同变形模式的相互作用所定义的VACNT阵列的复杂变形行为。发现加载速率和CNT附着在压头上对VACNT林的变形机制和整体机械性能有很大影响。与来自 仿真结果揭示了碳纳米管在束横截面上的整体屈曲的重要作用，以及由束不同变形模式的相互作用所定义的VACNT阵列的复杂变形行为。发现加载速率和CNT附着在压头上对VACNT林的变形机制和整体机械性能有很大影响。与来自对于模拟中预测的总体趋势和损耗系数的大小，进行了现场机械测试。森林形态可以强烈地改变具有名义上相同的一般特性（例如CNT半径，长度和材料密度）的VACNT阵列的机械性能，从而为通过微结构改性显着提高机械性能提供了机会。