This study analyzed the effect of incorporating graphene nanoplatelets in the fiber-matrix interphase on the behavior of a multiscale composite laminate based on carbon fibers and epoxy resin subjected to contact loads. The selected loading mode was the contact between an elastic surface and a cylinder. The multiscale composite material used was a quasi-isotropic laminate with graphene nanoplatelets (GnPs) added at the fiber-matrix interface. The specimens were prepared with 0.0%, 0.1%, and 0.25% by-weight GnPs. Laminate beams were used according to the ASTM D7264 standard, and contact was studied in two configurations, applying the load at the edge of the laminate and in the other, in the plane of the test pieces. The normal strains in the contact region were determined experimentally using the interferometric Moiré technique. These results were compared with estimations using the Hertz contact theory and the finite element method (FEM). The normal strains in the contact area of specimens with fibers modified with 0.1% GnPs were lower than those with 0.25% or fibers without surface modification. Excellent agreement between the experimental results along lines in the contact zone with those estimated with the FEM. The normal strains in a direction perpendicular to the applied load obtained by the Hertz theory for the maximum deformation were slightly higher than those obtained by FEM. Except for those calculated for the normal strain in εy for the load in the direction of the thickness, although the distribution was very similar to those obtained by FEM as well as the experimental one.

中文翻译：

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通过使用石墨烯纳米片改性纤维基体界面增强准各向同性碳纤维/环氧树脂基体层压板与弹性体的接触行为

本研究分析了在纤维基体界面中加入石墨烯纳米片对基于碳纤维和环氧树脂的多尺度复合材料层压板在接触载荷作用下的行为的影响。所选的加载模式是弹性表面和圆柱体之间的接触。所使用的多尺度复合材料是准各向同性层压材料，在纤维基体界面添加了石墨烯纳米片（GnP）。样品是用按重量计 0.0%、0.1% 和 0.25% 的 GnP 制备的。根据 ASTM D7264 标准使用层压梁，并在两种配置中研究接触，在层压板边缘施加载荷，在另一种配置中在试件平面上施加载荷。使用干涉莫尔技术通过实验确定接触区域的法向应变。将这些结果与使用赫兹接触理论和有限元方法 (FEM) 的估计结果进行比较。经 0.1% GnPs 改性的纤维试样接触面积的法向应变低于 0.25% GnPs 或未经表面改性的纤维。接触区沿线的实验结果与有限元法估计的结果非常吻合。通过赫兹理论获得的最大变形的垂直于施加载荷的方向的法向应变略高于通过有限元法获得的法向应变。除了 ε 中的法向应变计算值之外y对于厚度方向的载荷，尽管其分布与有限元法和实验获得的分布非常相似。