Study On Speech Clarity Of RTM-SEA Hybrid Method In Highspeed Railway Carriage

With the continuous improvement of the running speed of high-speed train,the problem of interior noise becomes more and more prominent.It has become an important development directions of rail transit to improve the sound field environment and ride comfort.As one of the important indicators to evaluate the quality of the sound field,it is necessary to carry out in-depth research on the language clarity inside the carriages.In this paper,based on the ray tracing method-statistical energy analysis(RTM-SEA)hybrid method,a prediction model of language articulation inside the high-speed railway carriages in the tunnel is established,and relevant parameters are simulated and analyzed.The main contents of this paper are as follows:Firstly,the sound insulation model based on the RTM-SEA hybrid method is established in VA One,and the theory is verified through the reverberation room sound insulation test,so as to ensure that the high-speed railway compartment model based on RTM-SEA can be predicted accurately and quickly.Secondly,based on above verification,a prediction model for the language clarity of high-speed railway carriages in the tunnel was established.The interior subsystems corresponding to different regions were divided,and the train surface was divided into FE planes;the pulsation pressure of train body surface structure is calculated,and with this data,the wave number-spectrum analysis is carried out,to obtain the general surface pressure data of train body SEA subsystem structure;based on the theory of equivalence,the key structures of the vehicle body,such as side wall,roof,floor and end wall,were modeled equivalent;in addition,modal test and vibration acoustic radiation test were carried out to obtain the modal density,damping loss factor and coupling loss factor,and then the above parameters were defined in the model as input.The actual sound excitation data outside the high-speed train running at 350km/h was used as input for calculation,and the prediction results of sound pressure level and speech articulation index(SII)in the high-speed train were compared with the actual measured data inside the train under running conditions to verify the correctness of the model.Then,with the aid of the prediction model,the influence of the in-train broadcast system of the high-speed rail on the in-train speech clarity under operating conditions is predicted and analyzed,and through the speech transmission index(STI),rapid speech transmission index(RASTI)and reverberation time(T30),the research and analysis of the speech clarity effects obtained from different sound sources,positions,and sitting and standing posture of passengers are carried out.It is found that the effect of speech intelligibility in standing posture is better than that in sitting posture.Through the comparison of male and female voices,it is concluded that female voice is more suitable for voice broadcast.Finally,in view of the shortcomings of the traditional A-weighted SPL standard in examining the effects of interior noise and speech clarity,the psychoacoustic parameters were proposed,and the loudness and sharpness parameters of three different positions in the front,middle and rear of the carriages were analyzed and evaluated.At the same time,VA ONE model combined with Matlab programming calculation and actual line operation experimental results were compared and verified to further ensure the correctness of the prediction model.In this paper,the prediction model of speech clarity in high-speed railway coaches in tunnels based on the hybrid method of ray tracing method and statistical energy analysis(RTM-SEA)is proposed,which can effectively predict the sound field parameters including language articulation,loudness and sharpness,and has practical engineering value.