Research On The Method Of Evaluation For Passenger Vehicles Door Closing Sound Quality

With the rapid development of the automotive industry,the automobile enterprise performance on NVH(Noise,Vibration,and Harshness)is not only limited to meet the requirements of noise regulations,But more and more focus on the subjective feelings of the car's sound quality.The quality of the closing sound is the main component of the sound quality of the car.The quality of its quality will directly affect people's judgment on the quality of the whole vehicle.Therefore,the quality of door closing sound has become a key research topic in the field of automobile noise and vibration control.In this thesis,the quality of passenger car closing sound has taken as the research object,and the research on the subjective and objective evaluation methods and the key research factors of the quality of the door closing sound has carried out.Firstly,taking the passenger car closing sound as the research object,a set of subjective evaluation test flow of closing door sound quality integrated with semantic differential and paired comparison method has proposed.Develop a test specification for the sound signal of the closing door sound signal,and establish a sound sample library for the subjective evaluation of the sound quality of the vehicle.According to the subjective evaluation,the multi-dimensional subjective perception attributes and the overall preference score of closing sound quality have obtained.Based on the correlation analysis between the subjective evaluation results,the multi-dimensional subjective perception attributes of metallic,rattle and duration sense related to the overall preference of closing sound quality have defined.Secondly,based on the time-frequency characteristic analysis of the transient pulse signal of the closed door,the acoustic objective characteristics corresponding to the multi-dimensional subjective perception attribute have obtained.Furthermore,through the application of the percentile frequency method and the geometric meaning of the second derivative of the function,the objective evaluation parameters of the corresponding sound quality have proposed,which have related to the metallic,rattle and duration of the subjective perception attribute of the door closing sound.They were 80 th APFC(Area of 80 th percentile frequency curve),2nd DASL(Area of 2nd derivative of specific loudness),and 10 th PLWT(Width of loudness vs.time at 10% of peak value).The correlation between the above evaluation parameters and the subjective evaluation results has verified.Then,based on the subjective evaluation results of the closed door sound and the proposed objective evaluation parameters,an objective prediction model that characterizes the subjective feeling of the vehicle closing sound quality is established by stepwise multiple linear regression method.The regression model adjusted multiple decision coefficients to 0.93,which achieves objective numerical quantification of subjective perception of closure door sound.Finally,through the closed-door acoustic diagnostic test and analysis,the relationship between the acoustic characteristics of the door closing system structure and the quality of the closed door has discussed.Combined with the subjective evaluation and sound quality prediction model analysis,the development strategy of the door structure for improving the closing sound quality has proposed,and the experimental support for the research on the production mechanism and sound quality development of the closing sound has provided.Through the subjective and objective evaluation research in this thesis,the objective evaluation parameters of multi-dimensional subjective perception attributes of closing sound quality are put forward,and the subjective preference score prediction model of closing sound is established,which realizes the objective numerical quantification of subjective feeling.Based on the analysis of closed-door acoustic diagnostic test,the basic development strategy to improve the quality of closed-door sound has put forward,which plays a guiding role in the development and design of closed-door sound quality.