Ductile Fracture in ASTM A992 Steel Tensile Specimens at Elevated Temperatures

摘要

Abstract This paper proposes a methodology for the prediction of ductile fracture observed in steel specimens during tension tests at elevated temperatures. This methodology consists of two steps. First, true stress–strain curves that include the post-necking response are developed at both ambient and elevated temperatures. Second, a stress-modified critical strain (SMCS) fracture model is calibrated and utilized to model the ductile fracture behavior of structural steels exposed to elevated temperatures. Development of true stress–strain curves and calibration of SMCS fracture model parameters are based on the tension tests data of ASTM A992 steel tension specimen together with the simulation results of the tested tension specimens in Abaqus at elevated temperatures. The developed true stress–strain curves and fracture model parameters are further validated against the additional test results of ASTM A992 steel in tension that were not used in the calibration of the fracture models. Sensitivity analysis on fracture prediction considering the effect of the mesh size and the variation of fracture model parameters are investigated. The analysis results suggest that the predicted fracture initiation strain is mildly sensitive to the effect of mesh size and variation of fracture model parameters. The robustness and limitations of the proposed methodology in predicting ductile fracture at elevated temperatures were further investigated. Overall, the developed methodology for ductile fracture in tensile specimens of ASTM A992 steel was demonstrated to reasonably predict tensile fracture at temperatures up to 1000°C.