Mechanical model for fracture toughness assessment
Keywords:fracture toughness, Brinell hardness, material properties degradation, low temperatures, thermoactivated plastic strain
Nuclear reactor vessels, transit oil or gas pipelines and many other high risk facilities tend to exhaust their design service life due to material properties degradation. The fracture toughness assessment for such equipment in operation poses a real technical challenge. The limited volume of materials which are available for testing, results in the need for small specimen technology. The method suggested is based on direct fracture toughness determination using very small specimens, at the liquid nitrogen temperature. After that, the KIC values at the operational temperatures can be calculated using the model proposed by the author.