Failure of polymers frequently initiates at discontinuities in the material, such as holes and notches, as they constitute points of increased stress concentration. Herein, we propose the use of monolayer graphene produced via Chemical Vapour Deposition to monitor the stress distribution close to a defect in poly(methyl methacrylate). Combining in-situ Raman spectroscopic mapping with tensile tests, the stress/strain distribution around the defect can be probed via monitoring the wavenumber shift of the spectroscopic features of graphene. The measured stress concentration factor of 2.41 is remarkably close to the value derived from Finite Element Analysis, and agrees with other studies in the literature, thus demonstrating that the proposed technique is reliable, and that graphene can accurately sense stress concentration close to a defect, with a sub-micron spatial resolution and a strain resolution of ≈ 60 με.

中文翻译：

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利用基于石墨烯的传感器监测具有圆形缺口的聚合物中的应力集中


聚合物的失效通常始于材料的不连续性，例如孔和缺口，因为它们构成了应力集中增加的点。在此，我们建议使用通过化学气相沉积生产的单层石墨烯来监测聚甲基丙烯酸甲酯缺陷附近的应力分布。将原位拉曼光谱映射与拉伸测试相结合，可以通过监测石墨烯光谱特征的波数偏移来探测缺陷周围的应力/应变分布。测得的应力集中因子 2.41 非常接近有限元分析得出的值，并与文献中的其他研究一致，从而证明所提出的技术是可靠的，石墨烯可以准确感知缺陷附近的应力集中，具有亚微米空间分辨率和 ≈ 60 με 的应变分辨率。