Vibration Analysis Of Semienclosed Noise Barriers Induced By High-speed Train Draft Pressure

Train draft pressure increases more and more quickly along with increasing speeds of trains,which in turn stimulates severe vibrations of track side structures.Noise barriers are generally installed near steel tracks to ensure efficiencies of noise reductions on rolling noises.However,with the stimulation of train draft pressure,noise barriers vibrate severely.Furthermore,semi-enclosed noise barriers have sealing characteristics which intend to increase the train draft pressure and may lead to more severe vibrations of structures.Therefore,this paper takes the semi-enclosed noise barriers located at Jinhua section of Hangzhou to Changsha high-speed railway as research objects to systematically investigate the vibration characteristics of semi-enclosed noise barriers induced by train draft pressure.The main contents are listed as follows:(1)The research backgrounds and significances are sketchily illustrated from three aspects which are the developments of high-speed railway,the feasibilities of noise barriers and the characteristics of high-speed train draft pressure.Current research status concerning about train draft pressure and train draft pressure induced vibrations of the noise barriers is summarized respectively,and relevant research methods are then summared for following applications.(2)The numerical model of train draft pressure inside the semi-enclosed noise barriers is developed by FLUENT on the basis of computation fluid dynamics(CFD).The presented way of modelling is calibrated by an existing engineering practice of noise barrier.Finally,the distribution characteristics of train draft pressure and the influences of operating lines and lengths of the top unit plates on the train draft pressure are analylzed and discussed.(3)With the simulated results of train draft pressure,the train draft pressure induced vibration analysis model is developed by ABAQUS.For model calibrations,in-site field test was carried out and the vibrations of the semi-enclosed noise barriers induced by high-speed trains are measured.The measured vibrations are then processed by lowpass filtering to get the vibrations of the semi-enclosed noise barriers induced by train draft pressure.(4)With the combination of the numerical models of train draft pressure and the semienclosed noise barriers,parameter studies are carried out to investigate the vibration characteristics of the semi-enclosed noise barriers and the influences of operating lines and lengths of the top unit plates on the vibration.The results show that the vibrations of the semi-enclosed noise barriers induced by train draft pressure only are largely influencd by the lengths of the top unit plates and the semi-enclosed noise barriers obtain the best mechanical property when there is only one top unit plate.The presented research results can be regarded as reference for mechanical design of the semi-enclosed noise barrier.