The rapid development of high-speed railway networks requires advanced methods for analysing vibration and sound radiation characteristics of a fast rotating train wheel subject to a vertical harmonic wheel-rail force...The rapid development of high-speed railway networks requires advanced methods for analysing vibration and sound radiation characteristics of a fast rotating train wheel subject to a vertical harmonic wheel-rail force. In order to consider the rotation of the wheel and at the same time increase the computational efficiency, a procedure is adapted in this paper taking advantage of the axial symmetry of the wheel. In this procedure, a recently developed 2.5D finite element method, which can consider wheel rotation but only requires a 2D mesh over a cross section containing the wheel axis, is used to calculate the vibration response of the wheel. Then, the vibration response of the wheel is taken as acoustic boundary condition and the 2.5D acoustic boundary element method, which only requires a 1D mesh over the boundary of the above cross section, is utilised to calculate the sound radiation of the wheel. These 2.5D methods and relevant programs are validated by comparing results from this procedure with those from conventional 3D analyses using commercial software. The comparison also demonstrates that these 2.5D methods have a much higher computational efficiency. Using the 2.5D methods, we study the wheel rotation speed influences on the factors including the vertical receptance of the wheel at wheel-rail contact point, sound pressure level at a pre-defined standard measurement point, radiated sound power level, directivity of the radia- tion, and contribution of each part of the wheel. It can be concluded that the wheel rotation speed splits most peaks of the vertical receptance at the wheel-rail contact point, sound pressure levels at the field, and the sound power level of the wheel into two peaks. The directivity and power contribution of the wheel are also significantly changed by the wheel rotation speed. Therefore, the rotation of a train wheel should be taken into account when calculating its vibration and sound radiation.展开更多
The rise of high-speed railway induces an increased probability of serious derailment accidents of operating high-speed trains during earthquakes.A two-and-half-dimensional finite element model(2.5D FEM)was developed ...The rise of high-speed railway induces an increased probability of serious derailment accidents of operating high-speed trains during earthquakes.A two-and-half-dimensional finite element model(2.5D FEM)was developed to investigate the ground vibration under combined seismic and high-speed train loads.Numerical examples were demonstrated and the proposed method was turned out to provide an effective means for estimating ground vibration caused by high-speed train load during earthquakes.The dynamic ground displacement caused by combined seismic and high-speed train loads increases with the increase of the train speed,and decreases with the increase of the stiffness of ground soil.Compared with the seismic load alone,the coupling effect of the seismic and high-speed train loads results in the low-frequency amplification of ground vibration.The moving train load dominants the medium–high frequency contents of the ground vibration induced by combined loads.It is observed that the coupling effects are significant as the train speed is higher than a critical speed.The critical train speed increases with the increase of the ground stiffness and the intensity of the input earthquake motion.展开更多
基金the support to this work from the Ministry of Science and Technology of China (2016YFE0205200)China Railway (2015Z003-B)Scientific Research Foundation of State Key Laboratory of Traction Power (2017TPL_T01)
文摘The rapid development of high-speed railway networks requires advanced methods for analysing vibration and sound radiation characteristics of a fast rotating train wheel subject to a vertical harmonic wheel-rail force. In order to consider the rotation of the wheel and at the same time increase the computational efficiency, a procedure is adapted in this paper taking advantage of the axial symmetry of the wheel. In this procedure, a recently developed 2.5D finite element method, which can consider wheel rotation but only requires a 2D mesh over a cross section containing the wheel axis, is used to calculate the vibration response of the wheel. Then, the vibration response of the wheel is taken as acoustic boundary condition and the 2.5D acoustic boundary element method, which only requires a 1D mesh over the boundary of the above cross section, is utilised to calculate the sound radiation of the wheel. These 2.5D methods and relevant programs are validated by comparing results from this procedure with those from conventional 3D analyses using commercial software. The comparison also demonstrates that these 2.5D methods have a much higher computational efficiency. Using the 2.5D methods, we study the wheel rotation speed influences on the factors including the vertical receptance of the wheel at wheel-rail contact point, sound pressure level at a pre-defined standard measurement point, radiated sound power level, directivity of the radia- tion, and contribution of each part of the wheel. It can be concluded that the wheel rotation speed splits most peaks of the vertical receptance at the wheel-rail contact point, sound pressure levels at the field, and the sound power level of the wheel into two peaks. The directivity and power contribution of the wheel are also significantly changed by the wheel rotation speed. Therefore, the rotation of a train wheel should be taken into account when calculating its vibration and sound radiation.
基金supported by National Natural Science Foundation of China(Grant Nos:41372271 and 51978510).
文摘The rise of high-speed railway induces an increased probability of serious derailment accidents of operating high-speed trains during earthquakes.A two-and-half-dimensional finite element model(2.5D FEM)was developed to investigate the ground vibration under combined seismic and high-speed train loads.Numerical examples were demonstrated and the proposed method was turned out to provide an effective means for estimating ground vibration caused by high-speed train load during earthquakes.The dynamic ground displacement caused by combined seismic and high-speed train loads increases with the increase of the train speed,and decreases with the increase of the stiffness of ground soil.Compared with the seismic load alone,the coupling effect of the seismic and high-speed train loads results in the low-frequency amplification of ground vibration.The moving train load dominants the medium–high frequency contents of the ground vibration induced by combined loads.It is observed that the coupling effects are significant as the train speed is higher than a critical speed.The critical train speed increases with the increase of the ground stiffness and the intensity of the input earthquake motion.
