Determination of Tensile Strength by Modified Brazilian Disc Method for Nuclear Graphite

Abstract

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.