Improved Finite Element Modelling of Tread Braked Wheel Performance Verified by Brake Rig Tests

Övrigt konferensbidrag, 2023

The objective of the present study is to validate a finite element material model for railway wheel steel against brake rig test results. The material model for pearlitic ER7 wheel steel has been calibrated for thermomechanical loading based upon the regulatory requirements for brake rig tests using specimen test results. The material model has shown better adherence to thermomechanical results compared to previous material models, but ultimately full-scale validation is required. To verify and further develop the model, a combined experimental and numerical campaign was launched. Using a custom-built brake rig at Chalmers University, two different designs of European freight wheels are tested at power levels of 30 and 50 kW for durations of up to 45 min with maximum temperatures exceeding 600 °C. Wheel rim displacements are measured during experiments and residual stresses are measured before and after each test using an instrument employing the elastoacoustic effect. Temperatures are measured using thermocouples on the wheel web, sliding thermocouples on the tread and a high-speed thermographic camera. The experimental results are then compared to finite element simulations at the same brake power levels using the aforementioned material model. The results show possible correspondence between the experimental and finite element results, indicating that the numerical model may be accurate enough for preliminary predictions of braking damage, while also highlighting challenges of thermal model assumptions.