基于流固耦合有限元法和集总参数法模型的建模方法

Modeling method based on fluid-structure coupling finite element method and lumped parameter method

传统的半主动悬置非线性较强,难以探究其动态特性。为了更好地解决其建模过程中参数识别困难的问题,根据半主动悬置的基本原理,采用一种基于流固耦合有限元法和集总参数模型的建模方法,对其运动特性进行了理论、仿真与试验研究。首先,根据悬置的基本原理构建了力学模型,在AMESim平台中建立了悬置结构集总参数模型;然后,采用流固耦合有限元法,提取了橡胶主簧、两个液室体积刚度、流体惯性系数和阻尼系数等关键参数;最后,将参数代入集总参数模型后完成了仿真,并通过搭建试验平台,验证了仿真结果的准确性;绘制了软硬模式下悬置系统的动刚度和阻尼角曲线,分析了其动态特性。试验结果表明:流固耦合-集总参数的建模方法精准度较高,仿真与试验对比后的动刚度和阻尼角最大误差分别为6.2%和7.4%,满足工程误差要求。研究结果表明:基于流固耦合有限元法和集总参数模型的方法不仅可用于分析悬置参数对动刚度和阻尼角的影响,也可为发动机悬置优化提供建模基础,节省了研发成本,提高了研发效率。

The traditional semi-active mount has strong nonlinearity,so it is difficult to explore its dynamic characteristics.In order to solve the difficult problem of parameter identification in the process of modeling,a modeling method based on fluid-structure coupling finite element method and lumped parameter model was used to study the motion characteristics of the semi-active suspension in theory,simulation and experiment.Firstly,the mechanical model was constructed according to the basic principle of mounting,and the modeling was completed in AMESim platform.Secondly,the key parameters such as rubber main spring,volume stiffness of two fluid chambers,fluid inertia coefficient and damping coefficient were extracted by fluid structure coupling finite element method.Finally,the parameters were brought into the lumped parameter model to complete the simulation,and the accuracy of the simulation results was verified by building a test platform.The dynamic characteristics of the mounting system were analyzed by plotting the dynamic stiffness and damping angle curves in soft and hard modes.The test results show that the modeling method of fluid structure coupling lumped parameters has high accuracy.The maximum errors of dynamic stiffness and damping angle after simulation and test are respectively 6.2%and 7.4%,which meet the engineering error requirements.The results show that this method based on fluid-structure coupling finite element method and lumped parameter model can not only be used to analyze the influence of mount parameters on dynamic stiffness and damping angle,but also provide a modeling basis for engine mount optimization,save research and development costs and improve research and development efficiency.