Use of artificial damping factors to enhance numerical stability for irregular joints

The authors previously proposed a fast and easy assembly method for wide flange steel column-beam frames in which the column and beam steel web had skew cuts and the lower flange of the steel beam was partially removed to prevent the bottom flange of the steel beam from running into the flanges of the L-shaped guide angles (which were pre-installed on the column bracket) when they were erected. However, the joint experienced convergence difficulties at the irregular structural configuration of the skewed web connections when cyclic finite element analysis was performed. This study introduced artificial damping factors, implemented during nonlinear numerical computation, to balance the internal and external forces. The influence of the damping factors was explored to ameliorate the numerical instabilities by removing the aforementioned convergence difficulties. It was shown that a solution converged while the dissipated stabilization energy was sufficiently small, ensuring that the analysis results were not distorted by the use of damping factors in the range of 1.0 × 10−5 to 5.0 × 10−5. The best matches with monotonic runs and the convergence for steels with yield strength of 325 MPa were obtained by applying damping factors of 0.0002 and 0.0005.