动力总成悬置系统非线性刚度设计及优化

Design and Optimization of Nonlinear Stiffness forPowertrain Mount System

汽车发动机的振动对车辆乘坐舒适性具有重要影响,如何有效地隔离发动机的振动是汽车设计中非常重要的问题。常用的方法是将动力总成悬置系统的刚度按线性变化设计,但这已不能满足目前隔振设计的发展需求,针对这一现状,基于非线性数学模型,提出一种悬置系统刚度设计和优化方法。首先建立动力总成悬置系统的动力学模型,得到系统非线性振动微分方程,为了控制各工况下动力总成质心的位移,根据悬置系统非线性刚度曲线的设计要求,对各悬置非线性段位移拐点和对应刚度进行设计;然后基于能量法解耦理论,在MATLAB中利用遗传算法对动力总成悬置系统各段的刚度进行优化;最后,将优化结果与其在ADAMS软件中的仿真结果对比验证。优化结果表明,动力总成悬置系统各个方向的解耦率均能达到设计要求,各段固有频率得到合理分配。

Engine vibration has a great influence on the ride comfort of automobiles.Effective vibration isolation of engines is a very important issue in automobile design.The common method is to design the stiffness of the powertrain mount system according to linear variation law,but it cannot meet the development needs of the current vibration isolation design.In response to this situation,based on nonlinear mathematical model,a design and optimization method for the stiffness of the mount system is proposed.Firstly,the dynamics model of the powertrain mount system is established,and the nonlinear vibration differential equation of the system is obtained.To control the displacement of the mass centroid of the powertrain under various working conditions,according to the design requirements of the nonlinear stiffness curve of the mount system,the displacement inflection point and the corresponding stiffness of each mount in nonlinear section are designed.Then,based on the decoupling theory of energy method,the stiffness of each section of the powertrain mount system is optimized by genetic algorithm in MATLAB.Finally,the optimization results are compared with the simulation results from the ADAMS software.The optimization results show that the decoupling rate of the powertrain mount system can meet the design requirements in all directions,and the natural frequencies of each section are properly allocated.