FINITE ELEMENT ANALYSIS ON ASEISMIC BEHAVIOR OF HIGH-STRENGTH STEEL BEAM-TO-COLUMN CONNECTIONS IN STEEL FRAMES BASED ON MICROMECHANICS OF FRACTURE

The fracture resistance of beam-to-column connections may affect the overall aseismic performance of steel frames directly, and it is essential for ensuring the design principle in terms of strong connections and weak members. In order to study the fracture behavior of high-strength (HS) steel frame beam-to-column connections subjected to cyclic loading, this paper uses cyclic void growth model (CVGM) to simulate the fracture of the connections. Through the finite element (FE) software ABAQUS, a 3D FE model of beam-to-column connection is developed, with the CVGM being embedded by using the USDFLD program. 21 specimens fabricated from different grades of steel with various configuration details are analyzed through the model and compared with the test results. It is indicated that load-deformation hysteresis curves, bearing capacities, and number of cycles before fracture commencing are in a good agreement with the tests. The results show that:the CVGM has good adequacy for simulating the extremely low-cycle fatigue fracture of the beam-to-column connections under cyclic loading, and it is suitable for different cyclic loading conditions and steel grades. A basic methodology and a valuable reference will be thusly provided for aseismic performance evaluation and anti-fracture design of the HS steel frame beam-to-column connections.