Determination of Plane-Strain Fracture Toughness Using Cracked Round Bar Specimens and their Applicability for Reliability Assessment Calculations

AbstractThe research work aimed to present the usability of the cracked round bar specimen type for the determination of the linear-elastic plain strain fracture toughness values on steels; and to demonstrate the applicability of the testing results for the reliability assessment of structural elements having cracks or crack like defects. Micro-alloyed structural steel and heat resistant steel were tested at elevated temperatures, at 260°C and 410°C, respectively, using small diameter specimens. Four different methods (equations) were used for the evaluation of the tests, and the determined fracture toughness values were compared with each other. Reliability assessment calculations were realised on two structural element models, critical crack sizes and safety factors were determined for all case