Difference of calculation results of crack tip opening displacement in domestic and foreign standards

The fracture toughness of 12Cr1MoV steel plate at different test temperatures was tested, and the crack tip opening displacement was calculated according to three standards and the difference was analyzed. The results show that the crack tip opening displacement calculated according to ASTM E1820-2020b and GB/T 21143-2014 standards was smaller, while the crack tip opening displacement calculated according to ISO 12135:2021 standard was larger. When the fracture toughness calculation result of the material was near the minimum allowable value of the crack tip opening displacement, the judgment conclusion would be inconsistent due to the different calculation criteria.