The impact of dissipative algorithms on assessment of high-speed train running safety on railway bridges

The global expansion of high -speed railway networks has elevated their significance as a primary mode of transportation, particularly concerning train running safety (TRS) on bridges during seismic events. Achieving an accurate simulation model for train-bridge coupled (TBC) systems is often hindered by oversimplified assumptions. Refined TBC modeling adds complexity to the relationship between train wheels and tracks, necessitating the discretization of continuous models. However, this process leads to numerical errors and overshooting phenomena, significantly affecting TRS assessment. To tackle these challenges, an efficient unconditionally stable explicit numerical dissipation algorithm is designed to minimize errors and mitigate overshooting in TRS calculations. Furthermore, three TRS indices, the derailment factor, offload factor, and velocity-related spectral intensity, are investigated using spectral radii. The results show that adjusting the spectral radius can effectively reduce false peaks in these indices. Nonetheless, excessively small values may lead to inaccurate TRS assessments. Comparative analysis reveals that setting the spectral radius to 0.5 achieves relatively precise TRS assessments. This study underscores the pivotal role of dissipative algorithms in the safety assessment of TBC systems, an aspect overlooked in previous research.