A simplified toughness estimation method based on standard tensile data. (October 2022) - Oh, Gyoko
Abstract: The toughness of a material is an important indicator for preventing sudden fractures or catastrophic failures. A simplified procedure for estimating the modulus of toughness K f using the divided area model was validated. The errors between estimations and measurements were small, indicating that this procedure can be used for predicting the toughness of various engineering materials. Using the specification data of mechanical properties in JIS and ASTM standards, the lower limits of modulus of toughness of typical structural steels were estimated and summarized in the forms of tables and figures for engineering applications. The square of estimated modulus of toughness was linearly correlated with the Charpy impact energy normalized by the yield stress σ y, and was directly proportional to the square of estimated fracture toughness K I c normalized by σ y as well. A formula was obtained as ( K I c / σ y ) 2 = α ( K f / σ y ) 2 = π rp, where rp was the plastic zone diameter according to Irwin's model, leading to a simplified method to estimate fracture toughness and critical distance. Highlights: A simplified method for estimating toughness was proposed with small errors. The divided area model can predict modulus of toughness using standard tensile data. Estimated modulus of toughness was linearly correlated with the impact energy. Fracture toughness was predicted with the modulus of toughness and yield stress.