Analysis And Optimization Of The Dynamic Comfort For The Driver Seat Of A Commercial Vehicle

With the rapid development of China's automobile industry,people are increasingly demanding to ride comfort.In the competitive automobile market,the difference between the use performance and the safety performance of different brand cars is very small.In contrast,the ride comfort of the automobile has become one of the important factors to distinguish the brand of the car.The seat is one of the main components that affect the ride comfort of the cars.Studying the comfort of the seat is of great significance for improving the riding comfort of the car.In this thesis,the modal of a commercial vehicle driver seat is analyzed and the lightweight design of the seat is designed.Then,according to the road test experiment feedback,the dynamic comfort problem of the seat is analyzed and optimized and the optimization scheme is verified.Firstly,the finite element model of the seat is established by using finite element software HyperMesh,and the modal of the seat is analyzed by MSC.Nastran software.The first order pitch mode of the seat is 18.51 Hz,the first order left and right swing mode is 21.13 Hz,the first order torsion mode is 47.48 Hz.Then the simulation results are verified by the seat modal experiment,the experimental results show that the maximum deviation between the modal analysis and the modal experimental results is only 6.99%.This indicates that the established finite element model can be trusted.Finally,the modal relative sensitivity of each part of the seat is calculated and the thickness of the seat parts is optimized according to the relative sensitivity.The lightweight of the seat skeleton is realized,the mass of the seat is reduced by 0.604kg(3.63 % of the total seat mass),and the modal calculation of the optimized model is carried out by MSC.Nastran software.The optimization results show that the qualit y of the seat is reduced and the modal performance is slightly declined.Secondly,in view of the poor dynamic comfort of the driver's seat in road test experiments,the comfort experiment of the "human seat" system is carried out by using random vibration signals to excite the vibration platform.The experimental results show that the dynamic comfort performance of the seat meets the design requirements.Then the Z direction acceleration transfer function between the suspension connection point and the seat installation point is calculated by MSC.Nastran.The results show that the maximum value of the acceleration transfer function of the seat installation point in the 0-30 Hz range is 0.006 g under the action of the Z direction of the front suspension connection point,and it does not meet the design requirements less than 0.005 g.Finally,the seat installation point is optimized,and the calculation results of the optimization scheme show that the optimization plan is effective.Finally,the road load spectrum is used to simulate the road test environment and the seat comfort experiment is carried out to verify that the seat mounting optimization scheme is effective.The load spectrum of the asphalt road and the undulating road was collected first,and the dynamic comfort of the seat was evaluated by using the collected load spectrum of asphalt road and the load spectrum of undulating road to excite the vibration table in the laboratory.By synthetically analyzing the experimental results of seat comfort under the excitation of two kinds of load spectrum,it is concluded that the comfort performance of the driver's seat of the commercial vehicle is better,so the optimized scheme is effective.