Analysis And Optimization Of Structural Performance Of Commercial Vehicle Cab

A commercial vehicle cab is chosen as the research object in this paper,starting from the static and dynamic characteristics and acoustic characteristics of the cab,the cab structure optimization and the integrated sound field control in cab are realized.A credible structure finite element model of cab body in white is established.The free modal and experimental modal analysis are carried out to verify the accuracy of the model and understand the dynamic characteristics of the body structure.The static characteristics of cab,such as modal,bending stiffness,torsional stiffness,and full-load static conditions of the cab under acceleration,braking,steering,and vertical impact,were analyzed.And for the analysis results,the lack of cab’s bending and torsional stiffness is discovered.Based on the analysis of the static and dynamic characteristics of the cab,a multiobjective topology optimization method is used to comprehensively optimize the structure of the cab.Firstly,an comprehensive objective function is established to realize the synergetic optimization of static stiffness and low-order vibration frequency.Second,through static and dynamic multi-objective topology optimization results analysis,we can find the weak position of the body structure,and then determine the structure that needs to be modified based on manufacturability,and propose a modification method.At the end of the optimization design,the bending stiffness and torsional stiffness of the body have been greatly improved.At the same time,the modal performance of the body has also been improved.The cab sound cavity and acoustic-structure coupled finite element model are established,and the NTF test is used to verify the accuracy of the model.The acoustic response of the cabin acoustic field was analyzed.The coupled and uncoupled sound pressures of the field points in the cab are calculated separately,and a comparative analysis is performed to find the peak frequency,and then the main noise reduction frequency is determined to specify the direction for the later optimization work.Based on ATV technology to analyze the contribution of panel to sound field in the cab.By combining the contribution of the integrated sound field at multiple sites and at multiple frequencies,the optimized key boards are determined.Based on the modal contribution analysis of MATV technology,the vibrational anti-node position of these panels is found and a free damping layer is applied on the anti-nodes.Finally,based on the cab interior noise response surface model,the thickness of the key panel and damping layer in the cab is optimized,and the optimized acoustic field in the cab is recalculated,which successfully suppresses the acoustic noise in the cab.