Verification and Parameter Selection of Stress Releasing Method for Vibration-based CWR

[Objective] To address issues with stress releasing approaches for the continuous welded rail (CWR), a novel vibration-based CWR stress releasing method is proposed, substituting the rail impactor with a vibrational exciter. [Method] Based on the on-site procedure, a CWR stress releasing finite element model is established. The measured locking rail temperature is incorporated to simulate the pre-operation non-uniform temperature stress state. Three stress releasing operational scenarios, namely natural tension, impact tension, and vibration tension, are set. The mean and standard deviation of temperature stress are set as evaluation indicators to compare and analyze the release effects under each operating condition, and to verify the feasibility of the proposed new stress release method. By changing exciter parameters (excitation force amplitude and frequency), a comparative analysis of the rail temperature stress mean value and standard deviation are carried out to determine the optimal excitation parameters of the proposed new stress release method. [Result & Conclusion] After the vibration-based CWR stress releasing operation, the mean and standard deviation of the rail temperature stress are significantly reduced, with the decrease values of 99.3% and 66.4% respectively, and the non-uniform temperature stress state of the rail is effectively improved. Certain influences of various excitation parameters on stress release effect are observed. The temperature stress release effect of the operating rail reaches the best when the excitation force amplitude is 5 kN and the excitation force frequency is 50 Hz.