Numerical prediction of thermal aging and cyclic loading effects on fracture toughness of cast stainless steel CF8A: Experimental and numerical study

• Published in: International journal of mechanical sciences Vol. 163; p. 105120
• Main Authors: Youn, Gyo-Geun, Nam, Hyun-Suk, Kim, Yun-Jae, Kim, Jin-Weon
• Format: Journal Article
• Language: English
• Published: Elsevier Ltd 01.11.2019
• Subjects: FE damage analysis; Monotonic and cyclic loading; Thermal aging effect on fracture toughness; FE damage analysis; Thermal aging effect on fracture toughness; Monotonic and cyclic loading
• ISSN: 0020-7403; 1879-2162
• DOI: 10.1016/j.ijmecsci.2019.105120

•The thermal ageing effect on fracture of CF8A under cyclic loading is numerically predicted.•A multi-axial fracture strain energy damage model is used in numerical prediction.•The damage model of un-aged CF8A is determined from tensile and C(T) test data under monotonic loading.•The damage model of aged CF8A is obtained by multiplying the thermal ageing constant by that of un-aged CF8A.•Predicted results agree with experimental results. This paper presents a FE simulation method to predict the thermal aging effect on fracture behavior of cast stainless steel CF8A under monotonic and very low-cyclic fatigue loading conditions. A multi-axial fracture strain energy damage model is determined from tensile and C(T) test data of un-aged CF8A under the monotonic loading condition. To simulate fracture behavior of aged CF8A, the multi-axial fracture strain energy of aged CF8A is obtained by multiplying the thermal aging constant determined from tensile test data by the multi-axial fracture strain energy of the unaged CF8A. The model is then extended to predict fracture behaviours of unaged and aged CF8A under fully-reversed cyclic loading. For the damage model, the model determined for the monotonic loading is applied to simulate fracture behavior under cyclic loading, based on the assumption that fracture energy is not dependent on the loading mode. It is shown that simulation results can capture the thermal aging effect on fracture behavior under monotonic and cyclic loading well. [Display omitted]