Simulation Study On Ride Comfort Of Four-axle Heavy Truck Semi-trailer Based On Filtered White Noise Method

With the continuous development of social economy,the logistics and trade activities among different places become more frequent.The use of multi-axle heavy semi-trailer train as a means of transport of bulk goods has become an important choice for the public.At the same time,vehicle ride comfort research has become a research hotspot for many scholars and heavy vehicle manufacturers to achieve commercial mode.Four-axle heavy truck semi-trailer train is a typical representative of heavy vehicles,and has a broad prospect in practical application.With the continuous development of computer simulation technology and its wide application in engineering practice,it is the development trend to improve the existing vehicle system by combining computer simulation technology with the study of the whole vehicle system and its diversification.It can not only effectively provide a more comprehensive calculation and verification for the existing or new vehicle structure,but also for the later scheme.Compared with optimization,it provides a theoretical basis and has a forward-looking significance for both existing and new models.This thesis has carried out in-depth exploration and Research on this aspect,and the specific research contents are as follows:(1)Analysis of dynamics equation of two-degree-of-freedom suspension system.The dynamic model and equation of the actual vehicle suspension are simplified,and then the harmonic excitation is used as the input function of the suspension.Finally,the vibration component response of the system is obtained.Through a simple two-degree-of-freedom system solution process,the multi-degree-of-freedom vibration component solution process is introduced,which lays a foundation for the subsequent vehicle structure dynamic equation solution and road random excitation model analysis.(2)Simulation of rough road surface model based on filtering white noise method.The process of building a rough road model will directly affect the reliability of vehicle performance in many tests,and then affect the simulation effect and evaluation of vehicle actual experiments.The content is mainly divided into two parts.The first part is the establishment of the model of uneven pavement based on filtering white noise method,and the excitation spectrum of grade D pavement is simulated by using MATLAB.The second part is the conversion of the excitation spectrum between the axes of the four-axle load-clamp dynamic model on the basis of the establishment of the model of uneven pavement.Through the analysis of the relevant content of this chapter,the excitation function is provided for the subsequent establishment of operational programming to carry out the dynamic response analysis of the vehicle under the random road surface.(3)Establishment of dynamic model and equation of four-axle semi-trailer with heavy truck.Among them,the parametric dynamic model of four-axle semi-trailer train with heavy trucks is composed of all parts of the body and parts.In the process of parametric simplification,the parts with vibration characteristics of the whole vehicle model are used as the support,and they are transformed into specific simple dynamic models.A spatial dynamic model is established for the key components of the actual vehicle system.Then a plane vehicle dynamic model and equation are established under the principle of limiting the working conditions and simplifying the calculation amount of repeatability.Finally,the multi-vibration response equation of the vehicle system is listed.(4)Ride comfort evaluation of vehicle system.The random excitation spectrum of grade D pavement with 40 km/h vehicle speed is established by using MATLAB software.The displacement,acceleration,relative dynamic load and dynamic deflection of each component under this condition are obtained by substituting it into the plane dynamic equation of the vehicle system.By fitting the results of relevant parts,the total weighted acceleration RMS of the seat is0.521m/s~2 and the equivalent mean is 115.6dB.Finally,the ride comfort of the whole vehicle system is evaluated.In summary,this thesis makes a comprehensive dynamic model analysis and Simulation of a four-axle heavy-truck semi-trailer train system,establishes a relevant road surface model-excitation spectrum of uneven road surface,and then carries out multi-stiffness dynamic modeling and equation solution of the system,finally obtains the vibration response results of each component of the vehicle system,and finally completes its ride comfort.Analysis of the results.This process can not only effectively shorten the design optimization cycle of related vehicles,but also save the cost of related experimental research and development,and provide a solid theoretical basis for the follow-up study of related fields of multiple models.