【作者】 李军；

【导师】 李兆军；

【作者基本信息】 广西大学 ， 车辆工程， 2019， 硕士

【摘要】 后扭力梁悬架作为汽车底盘的重要组成部件,在汽车运行过程中对于缓冲外激励带来的振动冲击,保证汽车的舒适性及安全性起到重要的作用。作为力、力矩的传递者及承担者,悬架在汽车行驶过程中持续承受着路面激励及发动机激励引起的振动冲击,激烈的振动尤其在共振的条件下极易致使悬架系统动态性能趋于复杂,动态性能的好坏不仅关系到汽车的安全舒适性更是直接影响到悬架本身的疲劳寿命。因此,在对悬架系统进行优化设计时,有必要探明整车影响下悬架系统的振动机理,考虑动力学特性的影响。本文旨在揭示悬架系统振动机理的基础上,综合悬架质量、固有频率、动态响应性能指标对悬架进行优化研究。主要内容如下:构建后扭力梁悬架的横梁单元及纵臂单元的有限元模型,并在所建横梁单元及纵臂单元有限元模型的基础上,考虑整车各部件之间相互作用、相互影响的耦合关系,应用有限元法建立能够反映悬架动力学性能与结构、材料、外激励参数之间内在关系的汽车后扭力梁悬架系统的动力学方程。根据所建汽车后扭力梁悬架系统的动力学方程,探究悬架系统在路面激励、发动机激励等外部激励作用下的振动机理,分析悬架系统在各种外部激励共同作用下的振动规律,探明悬架系统的动力学特性与结构参数、材料参数和外激励参数之间内在关系。在悬架系统动力学特性分析的基础上,结合解析法及差分法推导固有频率及位移响应对悬架系统结构参数的灵敏度表达式,探明悬架系统动态性能对结构参数的敏感度。对悬架优化设计过程中的关键技术参数进行分析,综合运用优化设计理论,在给定固有频率、动应力以及边界约束的条件下,建立了以悬架质量为优化目标,以横梁厚度、纵臂厚度、横梁位置等为设计变量的优化数学模型,确定能够满足悬架系统动态性能要求的优化设计方法。通过实例对汽车后扭力梁悬架系统的动力学特性及优化设计进行仿真分析,从而验证本文理论、方法的有效性及可行性。更多还原

【Abstract】 As an important part of automobile chassis,torsion beam rear suspension plays an important role in cushioning the vibration impact of road excitation and ensuring the comfort and safety of automobile.As the transmitter and undertaker of force and moment,suspension bears vibration impact produced by engine excitation and road excitation all the time during driving.Drastic vibration,especially resonance,easily cause the dynamic performance of suspension system to become particularly complex.The dynamic performance is not only related to the safety and comfort of the vehicle,but also directly affects the fatigue life of suspension.Therefore,when optimizing the suspension system,it is necessary to ascertain the vibration mechanism of the suspension system under the influence of the whole vehicle and consider the influence of dynamic characteristics.The purpose of this paper is to reveal the vibration mechanism of suspension system and optimize the suspension by synthesizing suspension mass,natural frequency and dynamic response performance index.The main contents are follows:The finite element model of beam element and longitudinal arm element of the torsion beam rear suspension is established.On this basis,considering the interaction between the components of the vehicle,the dynamic equation of vehicle torsion beam rear suspension system is established through the finite element method,which reflects the internal relationship between the dynamic performance of the suspension and the parameters of the structure,material and external excitation.According to the dynamic equation of the torsion beam rear suspension system,the vibration mechanism of the suspension system under road excitation and engine excitation is explored,the vibration law of the suspension system under is analyzed,and the internal relationship between the dynamic characteristics of the suspension system and the structural parameters,material parameters and external excitation parameters is proved.Based on the analysis of dynamic characteristics of suspension system,the sensitivity expressions of natural frequency and displacement response to structural parameters of suspension system are derived by combining analytical method and differential method,and the sensitivity of dynamic performance of suspension system to structural parameters is proved.The key technical parameters in the suspension design process are analyzed.With the optimization design theory and given natural frequency,dynamic stress and boundary constraints,an optimization mathematical model considering suspension mass as the optimization objective and beam thickness,longitudinal arm thickness and beam position as design variables is established and then the optimization method that improve the dynamic performance of suspension syste is determined.The dynamic characteristics and optimization design of the torsion beam rear suspension system are simulated by an example to verify the correctness of the theory research in this paper.更多还原