Role of elastic wave propagation on dynamic characteristics of train under a collision

Simplified rigid model of railway vehicles has been frequently utilized to examine train crashworthiness and to further optimize the energy distribution under a train collision. However, the effect of ignoring the elastic wave propagation on train crashworthiness performance is unclear. To address this limitation, a simplified one-dimensional elastic model is constructed and the effect of elastic wave propagation on energy absorption and dynamic characteristics of the train is investigated. Based on the classical elastic wave propagation theory, a law of scaling the density and elastic modulus accordingly to achieve the rod motion independence on its cross-sectional area is proposed. Then, the effect of elastic wave propagation speed on the energy absorption, stored elastic energy, and equilibrium velocity for a three-car-marshaling train collision under different impact velocities is discussed. It is found that the elastic wave propagation speed of approximately 3500 m/s has the best accordance with the real train model. The relative errors of absorbed energy of the simplified one-dimensional elastic model in comparison to that of the real train mode are only 2.56%, 1.84% and 1.45% under initial impact velocity 10 m/s, 15 m/s, 20 m/s, while the absorbed energy of the simplified rigid model is 10.7%, 12.4% and 14.8% higher than that of the real train model, illustrating that the rigid model significantly overestimates the absorbed energy. Our results can advance the crashworthiness design and optimization of the train under collisions.