A numerical model to study the effects of low temperatures on bridge-borne noise in railways

Structure-borne noise radiating from the bridge is one of the main noise sources in railway. Especially in cold regions, the fragile ecosystems can be damaged by such low frequency noise. To control the noise radiation from bridges at low temperature, a detailed numerical method for noise prediction is needed. This paper proposes a model that considers the effects of elastic temperature-varying materials on the vibration response and noise radiation of bridges. It was validated by comparing the measured results with the results simulated by the prediction model. First, it was found by using three-dimensional vehicle-track-bridge coupled dynamic model that the stiffness and damping of the fastener pads and bridge supports have a complex effect on the dynamic characteristics of the track structure and bridges at low temperature. Then, it was found by using boundary element noise prediction model that different air density changes the directivity and attenuation of bridge -borne noise. The results indicated that as the temperature drops from 20 to -50, the sound pressure level of bridge noise decreases initially, followed by an increase, but then again decreases.