The Brazilian disc test has been used widely to measure the tensile strength of brittle materials, such as rock and ceramic. However, the Brazilian disc method developed for rock has not been applicable for nuclear graphite due to the large ratio of tensile to compressive strength in the material. According to the results of stress analysis and Griffith’s strength criteria, the graphite compressive stress near the contact area must be decreased for the Brazilian tensile strength method. In this paper, the Brazilian disc test has been modified by using a newly developed anvil with a V-shaped cavity. According to finite element analysis, the stress concentration around the contact area between graphite samples and anvils was significantly reduced by the new design of anvils. The design has been proved to be effective by comparing with the direct methods. The method also has been proved to be valid for different samples sizes considered in this study, which indicates that it has a wide applicability.

中文翻译：

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用改良巴西圆盘法测定核石墨的抗拉强度

巴西圆盘试验已广泛用于测量脆性材料（如岩石和陶瓷）的抗拉强度。然而，由于材料中的抗拉强度与抗压强度之比较大，为岩石开发的巴西圆盘法不适用于核石墨。根据应力分析结果和格里菲斯强度准则，巴西抗拉强度法必须降低接触区附近的石墨压应力。在本文中，巴西圆盘测试已通过使用新开发的带有 V 形腔的砧座进行了修改。根据有限元分析，新设计的砧座显着降低了石墨样品与砧座接触区域周围的应力集中。通过与直接方法的比较，证明该设计是有效的。该方法也被证明适用于本研究中考虑的不同样本量，这表明它具有广泛的适用性。