In this study, the loading rate sensitivity of the mode II fracture behaviour of composites toughened by carbon nanotubes (CNTs) was investigated. CNTs were inserted into laminates in the form of films. The specimens for the mode II fracture test were subjected to loading rates varying from the quasi-static 8 × 10⁻⁶ m/s) to dynamic (15 m/s) states using an Instron machine and electromagnetic Hopkinson bar, respectively. Under the quasi-static loading conditions, the fracture toughness of the composites increased monotonously with an increase in the number of CNT layers and approached a maximum value when 30 layers of the CNT film were added, which is twice the value of the virgin specimen (without CNTs). However, under the dynamic loading conditions, the fracture toughness of the composites improved only by 25% compared with that of the virgin specimen, and the change in the number of CNT layers had little effect on the fracture toughness of the composites. This indicated that under dynamic loading, the failure mode of the interlaminar region changed. Microscope observation results illustrate that a large amount of in-plane (x-y plane) shear failure occurs in the CNT-interleaved zone under the dynamic loading conditions.

在这项研究中，研究了碳纳米管 (CNT) 增韧复合材料的 II 型断裂行为的加载速率敏感性。碳纳米管以薄膜的形式插入层压板中。用于模式 II 断裂试验的试样经受从准静态 8 × 10 ^-6 m/s) 到动态 (15 m/s) 状态，分别使用 Instron 机器和电磁霍普金森棒。在准静态加载条件下，复合材料的断裂韧性随着CNT层数的增加而单调增加，当加入30层CNT薄膜时接近最大值，是原始试样的两倍（没有碳纳米管）。然而，在动态加载条件下，复合材料的断裂韧性与原始试样相比仅提高了 25%，且 CNT 层数的变化对复合材料的断裂韧性影响不大。这表明在动态载荷作用下，层间区域的破坏模式发生了变化。