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Volume Title: ICASGE2021

DOI: ICASGE-STL

HaoMin Ding; Bo Yang; DeYang Kong; ¹HaoMin Ding; ²Bo Yang

¹School of Civil Engineering, Chongqing University, Chongqing 400045, China

²School of Civil Engineering, Chongqing University, Chongqing, China

The ductile fracture characteristics of grade 8.8 high strength bolt materials under quasi-static condition were studied through mechanical property tests of six kinds of specimens with different notches. Then Swift, Voce, and mixed Swift-Voce hardening model were respectively used to fit the stress-strain curves of the smooth round bar specimen. In comparison, the mixed Swift-Voce hardening model showed the best accuracy in simulating the load-displacement curves of all specimens. The mean stress triaxiality and Lode parameters of the critical element can be obtained by the finite element model of the specimen. In addition, VGM model, Kong model and Lou model were calibrated, and after that, the three fracture models were used to predict the fracture of all specimens. The results showed that both Lode parameters and stress triaxiality were important factors affecting the fracture performance of the specimens, and the introduction of Lode parameters to the fracture model could effectively improve the accuracy of fracture prediction of tensile shear plate specimens.

Grade 8.8 high strength bolt; Stress triaxiality; Lode parameter; Ductile fracture