The effects of railway car-body flexibility on the dynamic analysis of high-speed trains traveling on bridges are studied. The flexible car-body is modeled as a uniform beam supported by the primary and secondary suspensions. A parametric sensitivity study is carried out to examine the effects of different parameters, namely the track irregularity, rail joint, traveling speed and the wheel flat, on the dynamic responses of the car-body and bridge. The rail surface roughness is regenerated by its power spectral density. Different types of rail joint geometries and wheel imperfections are mathematically modeled and included in the numerical simulation. It is found that the flexural mode shapes of the body structure can remarkably affect the calculated ride comfort index especially in the low frequency range.

Application of the piezoelectric patch to mitigate the train wheel squeal is presented in this paper. A complete model for the wheel, rail and foundation is employed in the frequency domain. The wheel squeal model with the shunted piezoelectric element is presented and the consequent added damping is calculated for the critical frequencies. Two different shunt circuits including the resistor ([Formula: see text] and resistor–inductor (RL) are applied and the consequent performances in the noise mitigation are evaluated for different frequencies. The effect of contact point lateral displacement on occurrence of the wheel squeal is investigated. In the parametric study, the effects of shunting circuit and its parameters, size, position and number of piezoelectric elements on the control performance are evaluated. It is found that the resistance shunt circuit has optimal performance when the added damping over a broadband frequency range is implemented. In addition, both the added damping and added damping per piezoelectric volume become saturated by increasing the number of piezoelectric patches further over a specific limiting value.

Application of a shunted piezoelectric system in reduction of the squeal noise level in railway wheels is studied. A wheel squeal model including the railway track, wheel, and nonlinear interaction contact forces is taken into account in the time domain. Consequent vibration of the wheel is calculated at incident of sharp curve passing. The sound pressure level (SPL) of the noise is then calculated by an analytical method. Performance of different shunt circuits including the R (resistance) and RL (resistance inductance) is evaluated in different frequency ranges. A new methodology is proposed to achieve multimode damping. According to results, the SPL of wheel squeal noise can effectively get reduced by the proposed method, up to 5 dB at near-field and 10 dB at far-field.

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