The present paper describes detailed analyses of experimental data for the cyclic-fatigue behaviour of epoxy nanocomposite polymers. It has been shown that the data may be interpreted using the Hartman–Schijve relationship to yield a unique, ‘master’, linear relationship for each epoxy nanocomposite polymer. By fitting the experimental data to the Hartman–Schijve relationship, two key materials parameters may be deduced: (i) the term A, which may be thought of as the fatigue equivalent to the quasi-static value of the fracture energy, G_c, and (ii) the fatigue threshold value, $\mathrm{\Delta }\sqrt{G_{\text{thr}}}$, below which no significant fatigue crack growth (FCG) occurs. It has then been established that the values of these parameters, together with the slope, n, and intercept, D, of the Hartman–Schijve master relationship, may be used (i) to compute the experimental results measured for the fatigue behaviour of the epoxy nanocomposite polymers, (ii) to understand the observed fracture and fatigue behaviour of these materials with respect to the structure of the epoxy nanocomposite polymers, and (iii) to deduce the ‘upper-bound’, i.e. ‘worst-case’, FCG rate curve which may be used by industry as a material development, material selection, design and service-life prediction tool when these epoxy nanocomposite polymers are used in engineering applications such as structural adhesives and/or as matrices in fibre-reinforced composites.

This article is part of a discussion meeting issue ‘A cracking approach to inventing new tough materials: fracture stranger than friction’.

本文描述了环氧纳米复合聚合物循环疲劳行为的实验数据的详细分析。已经表明，可以使用 Hartman-Schijve 关系来解释数据，从而为每种环氧纳米复合聚合物产生独特的“主”线性关系。通过将实验数据拟合到 Hartman-Schijve 关系，可以推导出两个关键的材料参数：（i）A 项，它可以被认为是等效于断裂能准静态值G _c的疲劳， (ii) 疲劳阈值，$\mathrm{\Delta }\sqrt{G_{\text{thr}}}$，低于此值不会发生显着的疲劳裂纹扩展 (FCG)。然后已经确定这些参数的值以及斜率n和截距D，Hartman-Schijve 主关系，可用于 (i) 计算测量环氧纳米复合聚合物疲劳行为的实验结果，(ii) 了解观察到的这些材料相对于结构的断裂和疲劳行为环氧纳米复合聚合物，以及 (iii) 推导出“上限”，即“最坏情况”，FCG 速率曲线，该曲线可被工业用作材料开发、材料选择、设计和使用寿命预测工具当这些环氧纳米复合聚合物用于工程应用时，例如结构粘合剂和/或作为纤维增强复合材料中的基质。

这篇文章是讨论会问题“发明新的坚韧材料的破解方法：断裂比摩擦更奇怪”的一部分。