Research On Optimization Design Of Bus Body Structure

Safety,comfort,energy saving and environmental protection are the main trends of the car.In order to improve the safety and comfort,carry out research on two aspects for the bus.One is the rollover condition which is very dangerous in the traffic accident.The other is the noise which influences the ride comfort.Vehicle rollover is one of the most harmful in all crashes.When the upper body strength was increased,body deformation can be reduced.In this way,it can reduce the harmfulness to passengers in vehicle rollover.With the living circumstances improving,people become more demanded for riding comfort.The strength and vibration characteristics of the vehicle body are the main factors of rollover and noise.In order to improve the safety and ride comfort,improvement of structure of bus body is implemented in this paper.The main research contents are as follows:A simulation finite element model of bus was set up by the software named Hypermesh,then strength of the upper part of the bus body was analyzed.According to the standard of "Superstructure strength of passenger car",the passenger car rollover model was established.And the strength of the upper structure of the passenger car was evaluated by the distance between the column and the living space.Ceiling bracing arrangement? ceiling and column bracing arrangement and curved corners arrangement were put forward.Through the evaluation and analysis,it was concluded that the addition of the bracing between the ceiling and the side arrangement can effectively improve the strength of the upper part of the vehicle body structure.Vehicle's interior noise was analyzed based on the theory of the noise transfer function(NTF),the operational deflection shape(ODS)and the participation factor panel(PFP)synthetically.The main noise sites of analysis include the point at driver's right ear and points at the front row of the passenger area and the rear row right ear.Count noise peak frequency point and use the body deformation and the panel contribution analysis method to determine the structures that contribute large noise.Through the in-vehicle field analysis,the maximum noise position was the ceiling position.Through the above two studies,it is necessary to optimize the structure for the ceiling.By the modal analysis research on different arrangements of roof beam,it is concluded that the distribution frequency of the uniform beam and the biased longitudinal beam was quite different.According to the results of analysis by noise transfer function,the uniform arrangement of the longitudinal beam can reduce the noise peak inside the car.In this paper,the optimized structures of bus roof components were first designed.Then,the safety and the noise level of the passenger car were evaluated respectively.Finally,the bus structure which can not only improve the performance of safety in rollover condition but reduce the noise was figured out.This research shows important academic value and practical significance to improve the comfort and safety of passenger cars.