Research On Structure-Borne Noise And Airborne Noise Of Excavator Cab

Structurre-borne noise and airborne noise are the main components of the cab’s ear noise,which seriously affect the driver’s work efficiency and physical and mental health.It must be analyzed,evaluated and improved in the pre-design phase of the cab.Its related research is of great significance to the improvement of the performance of excavator NVH(Noise,Vibration,Harshness).The cab is a closed space enclosed by panels.Studying the structurre-borne noise and airborne noise of the cab has certain engineering practical value for improving the noise level of the excavator cab.Based on the actual engineering project of performance improvement of excavator products,the paper studies the influencing factors of noise structure and noise sound field in the driver’s ear,and analyzes the cab structure and noise sound field of a certain type of excavator.Taking the excavator cab as the research object,the vibration characteristics of the cab structure and the sound chamber of the excavator are simulated and analyzed,and the structural influence factors of the driver’s ear noise are found.To improve the noise of the cab driver’s ear,the numerical simulation analysis of the structure-borne sound field and the airborne noise sound field is carried out respectively from the composition of the noise,and the relationship between the ear noise,the structure-borne and the airborne noise is obtained,and the data collected by the structural test test verifies the feasibility of the research idea;According to the results of simulation and experiment,the research goal of improving the noise of the cab driver’s ear is achieved through the modification of the cab structure.Firstly,based on the research ideas of the cab noise around the ear improved by s structure-borne and the airborne noise,combined with the structural characteristics of the cab itself.Theoretical model about the structural modal and acoustic cavity modal analysis,structured sound field and airborne sound field numerical simulation analysis are established.The modal theory is used to analyze the structural rationality of the excavator cab,and the sound field characteristics of the excavator cab are analyzed by the plate radiation theory and transmission theory.Secondly,the excavator cab model is established,and the modal analysis method is used to simulate the cab modal and acoustic cavity modes respectively.The structural factors affecting the driver’s ear noise are found by analyzing the vibration characteristics of the cab structure and the acoustic cavity.Using the actual vibration and noise signals collected by the test as excitation,the direct frequency response analysis method is used to simulate the sound field of the cab about structure-borne and the airborne noise.Combined with the measured ear noise,the relationship between ear noise,structure-borne and the airborne noise is determined.Finally,according to the analysis results of the structural influence factors of the ear noise and the relationship between the ear noise,structure-borne and the airborne noise,the structural modification of the floor and the rear glass of the excavator cab is carried out.The simulation calculation is carried out for the restructured structure.Comparing the data before and after optimization,structure-borne and the airborne noise of the cab are improved to different extents,and the research goal of improving the noise of the ear is achieved.In this paper,the structure-borne and airborne sound field of the excavator cab are studied.Combined with the analysis of the structural characteristics of the cab,the analysis method for the research of the driver’s ear noise in the excavator cab can be proposed through simulation analysis and experiment.The results show that the cab sound field analysis combined with the cab modal analysis can effectively predict the driver’s ear noise,combined with structural rectification and other measures to improve the driver’s ear noise.