| This paper takes a multi-function semi-trailer car transporter as the research object and focuses on the problems existing in the use of this type of car transporter.Firstly,the force of the vehicle under the lifting condition was analyzed,and the multi-body dynamics software ADAMS was used to establish the dynamics model of the rear lifting mechanism of the car transporter,analyze the causes of the problem,and put forward the improvement scheme.Then,the finite element model of car transporter body structure is established by ANSYS software,and the dynamic strength analysis under four typical working conditions and free modal analysis are carried out.The main research contents and conclusions are as follows:(1)Firstly,through the load analysis of the rear lifting mechanism,the force of the rear lifting mechanism at different heights is obtained.After that,the virtual prototype model of lifting mechanism is established by using ADAMS software,and the dynamic simulation analysis is carried out.Through the analysis,the causes of the rear lifting mechanism in the middle lifting stage are found out.In order to improve the lifting scheme and optimize the lifting performance,the combined lifting mechanism of rear-push connecting rod to replace the four-bar lifting mechanism.Through comparative analysis,it can be seen that the horizontal force of the lifting mechanism on the front column is reduced from 55.2kN to 14.69kN,and the required cylinder thrust is 110.2kN,which is 11.4%lower.Moreover,the lifting mechanism starts faster and the lifting is more stable.In order to verify the stability of the new lifting mechanism,a lifting test sample vehicle was established,and the lifting test was carried out to further verify the feasibility of the new lifting mechanism.(2)After that,according to the geometric model of the semi-trailer car body structure,the finite element model of the semi-trailer car body structure is established by using ANSYS software,the method of structural connection is studied and simulated,and the dynamic strength analysis of the body structure under various limit conditions is carried out.According to the analysis results,the comprehensive evaluation of the strength and stiffness of the body shows that the maximum stress of the body under various limit conditions is lower than the yield strength of the material,which meets the requirements of use.After that,the influence of the combined lifting mechanism of rear-push connecting rod on the stiffness,strength and stability of the body is analyzed.It can be seen that the stress and deformation of the improved body structure are reduced.Through the road driving test,the body structure can meet the requirements of use.(3)Subsequently,in the free state,the modal analysis of the semi-trailer car body is carried out,and the first 14 modal vibration modes and natural frequencies of the body are obtained.Through the evaluation principle of modal analysis,the results of modal analysis are checked.It is verified that the low-order frequency of the body can avoid overlapping with the idle frequency of the engine and the excitation frequency of the road,so as to avoid resonance.By analyzing the natural frequency,vibration mode and other relevant parameters,we know the shortcomings of the dynamics of the semi-trailer car transporter.(4)Finally,in order to make the structure strength and layout of the car body better meet the use requirements of the whole vehicle,reduce the design cycle and cost,based on the analysis of the existing body structure,a car body structure with fully articulated lifting mechanism is proposed.This paper introduces the technical scheme and advantages of the body structure of the fully articulated lifting mechanism,and rebuilds the finite element model with ANSYS,analyzes its static and dynamic characteristics,and checks the bending stiffness and torsional stiffness of the upper platform and the lower frame.The results show that the stress distribution of the body structure of the fully articulated lifting mechanism is more reasonable,the strength is higher,and the body deformation is smaller,which provides a good reference for the follow-up research of this kind of car body structure. |
PDF Full Text Request