Numerical simulation of quasi-static tests of Y-type RHS connections

Finite element (FE) method for simulating the hysteretic behavior of Y-type RHS (rectangular hollow section) connections accurately is presented in this paper. For analyzing the seismic behavior of tubular structures, quasi-static tests on Y-type RHS connections were carried out by the authors. In the tests, cracks appeared in the chord connecting surface, and extended along the connecting weld between the brace and chord, which caused the performance degradation and failure of the connection. To simulate the damage accumulation of steel and crack propagation, simplified Lemaitre's damage model is incorporated into a constitutive model subroutine in ANSYS. Using the material properties from the tensile test, an approximation method for calculating the damage material parameters is proposed. The quasi-static tests are simulated using above material subroutine. Hysteretic curves from FE analysis agree well with the experimental curves.