| Using the general software ANSYS parametric design language APDL and user programmable function UPFs, elliptical yield model was compiled into ANSYS as a subroutine module. The program establishment was realized by the open programming interface of ANSYS software. Through numerical simulation and fracture analysis of test of beam-column connection, the modified coefficient of elliptical fracture model was obtained by equivalently calculate the effects of residual stress and disfigurement. Joints of steel beam-square column filled with concretewere numerical simulated and analyzed based on generalized strength model. Numerical results show that the strong constraint of column on the beam leads to high stress concentration in beam flange butt weld, where the equivalent stress and the average stress amplitude are high. The butt weld fractured when the stress function reached the critical value of ellipsoidal fracture model.Using the ellipsoidal fracture model for evaluation, the new connections with holes on flange and web are put forward. On the basis of damage mechanism of beam-to-column connections, the finite element parameters of the new kind of nodes are studied. The influences of weakened parameters on stress behavior are discussed, the details of connection are proposed to reduce equivalent stress and average stress amplitude in butt weld.According to the results of finite element analysis, six joints with 1/2 scale of modeling for the practical project have been tested under cyclic-loading. The fracture behavior of butt weld and the plastic deformation of flange and web with hole have been studied. The experimental results indicated that this new kind of connections has excellent energy dissipation capacity and anti-seismic performance and plastic rotation satisfied requirement of the structure anti-seismic design. The experimental results are in good accordance with calculated values of finite elemen. |
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