Analysis And Optimization Of Interior Noise Sound Quality Of Special Vehicle

Due to the specific use of special vehicles,many governments and enterprises began to strictly control the noise and vibration of special vehicles.The operating environment of special vehicles is often worse than that of passenger or commercial vehicles,and the noise in the cab seriously affects the physical and mental health of drivers.There are few studies on the prediction of the interior sound quality of special vehicles.This dissertation analyzes the interior sound quality of a special vehicle and establishes a prediction model for subsequent optimization research.The main research contents are as follows:First of all,the interior noise acquisition experiment is carried out and the test data are selected,processing into 68 valid sound samples which could be subjected to subjective evaluation test,to determine the rating scale for the subjective evaluation method.After the evaluation by 25 evaluators,the correlation analysis of the obtained evaluation results is carried out,finally retain and calculate the 20 personnel’s subjective grading arithmetic mean value,used as the output value of the subsequent prediction model.The A-weighted sound pressure level,loudness,sharpness,roughness and Articulation Index of the sound samples were analyzed and calculated,and then used as the input values of the subsequent prediction model,finally the variation trend of each parameter with the working condition is analyzed,which provides theoretical support for the establishment of subsequent prediction model.Second,XGBoost algorithm is used to construct a prediction model for the interior noise quality of special vehicles.The comparative analysis show that the prediction accuracy of the XGBoost model is better than that of the random forest model and the linear regression model,with an average relative error of 2.43% and a decision coefficient of 0.943.According to the characteristics of objective parameters of sound quality,A-weighted sound pressure level,loudness and sharpness contribute more to the prediction of subjective score.Finally,based on sound absorption performance test adopted PET,EVA,felt,needle blanket face four kinds of material,adding in the corresponding position of special vehicle interior noise again after acquisition and obtain objective parameters of psychoacoustics,through the analysis and comparison of the special vehicle engine constant speed three working conditions as a result,A-weighted sound pressure level decrease()0.96 d B A,the largest loudness decrease1.826 sone,the largest sharpness reduce0.109 acum,the largest roughness decrease 0.085 asper,the largest Articulation Index enhance 4.051%.The prediction results of XGBoost model show that the subjective evaluation score is increased by 0.73 points at most and 0.35 points on average,which indicates that the optimization scheme of the acoustic packaging for the interior sound quality of the special vehicle is effective to some extent.