Dynamic Analysis And Vibration Suppression Design Of A Light Truck

The ride comfort of light truck not only determines the comfort feeling of the driver,but also has an important impact on the reliability of the structures and the safety of the transportation goods.There is a similar abnormal vibration problem in several kinds of light truck produced by an enterprise,and its main forms of the abnormal vibration are as follows: the vibration of these truck is not obvious when driving on bad road,but abnormal vibration is obvious when these trucks is driving on flat road,and in a certain speed range,the vibration amplitude is abnormally large.Aiming at this problem,the method of combining finite element numerical simulation and vibration test experiment was used to determine the vibration source and transmission path of the abnormal vibration problem of these light trucks.Then,based on the complex modal theory,the suspension parameters of the light truck was optimized,and through the analysis of examples showed that the vibration suppression design can achieve significant results.The main contents of this thesis are as follows:(1)Based on the finite element complex modal analysis and harmonic response analysis,the vibration characteristics of the light truck were analyzed.According to the forms and characteristics of the abnormal vibration problem of the truck,and combining with the parameters of the light truck provided by the enterprise,the truck model was established.Then,the natural vibration characteristic of the truck model was calculated by complex modal analysis and harmonic response analysis,and the vibration response of the cab under the excitation of the wheel's radial runout was explored,the cause of the abnormal vibration problem was identified.Finally,based on the results of analyses,the relationship between suspension system parameters and vibration response characteristics of truck was explored.(2)Based on the vibration test of the light truck,the abnormal vibration problem was analyzed and diagnosed.In order to ensure the reliability of finite element analysis,designed and conducted light truck vibration test experiments in cooperation with enterprises.By analyzing the data of the test results,the forms and characteristics of the abnormal vibration were determined,the vibration characteristic parameters of the truck were obtained,the causes of the abnormal vibration problem of the light truck were further determined,and the results of finite element analysis were verified.(3)The suspension parameters optimization model was established,and vibration suppression design of example was carried out.Based on the results of vibration test analysis and finite element analysis,the half car 2 degree-of-freedom dynamic model was established,and simulating wheels radial run out excitation with sine sweep excitation,taking the seats weighted acceleration mean square value and cargo box acceleration mean square value for evaluation index of driving smoothness,and taking the loading capacity,assembly technique condition and the fundamental dynamic characteristics requirements for constraints,the suspension parameters optimization model was established.Finally,take a light truck as an example,optimized its suspension system parameters,and the vibration characteristics parameters of the light truck were compared before and after optimization.The results showed that the optimization method can effectively solve the problem of abnormal vertical periodic vibration of light truck and improve the ride comfort of light truck.