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Fatigue Crack Propagation and Life Analysis of Stud Connectors in Steel-Concrete Composite Structures

To investigate the fatigue performance of the stud connectors of steel-concrete structures, fatigue crack propagation analysis and fatigue life calculation were carried out. Firstly, the finite element model with the initial crack based on linear elastic fracture mechanics (LEFM) was established, and the parameter analysis of the stress intensity factors (SIFs) of the studs and cracks with different geometric sizes was performed. Then, the propagation with mixed-type fatigue crack and I-type fatigue crack of the stud were calculated, and the variation of effective SIFs with the fatigue crack depth was analyzed. Finally, the flow chart of stud fatigue life evaluation which considers crack initiation and stable propagation was presented, and the short stud of steel-UHPC composite structures was taken as an example and verified. The calculation results show that the fatigue crack propagation type and the initial crack have an obvious influence on the fatigue life of the stud. It has acceptable accuracy that the fatigue life of short stud in UHPC simulated by considering the crack initiation. The critical damage parameters are greatly affected by the fatigue stress amplitude, and the initiation life of fatigue crack can account for more than 90% of the total fatigue life. This paper can provide a reference for evaluating the fatigue performance of studs in steel-concrete composite structures. Accurate evaluation of the fatigue life of stud connectors conforms to the concept of sustainable development.