某乘用车排气系统振动性能的优化

Vibration Performance Optimization of Exhaust System in a Passenger Car

为改进某乘用车排气系统的振动性能,建立了其有限元模型,用Nastran软件进行静力学和动力学计算、吊耳位置评估和排气系统的运动包络面计算。以最小化挂钩垂向动态载荷最大值与标准差和吊耳的静变形量与预载力标准差为目标,以吊耳隔振量不小于20dB为约束条件,以吊耳和波纹管动刚度为优化变量,建立了排气系统振动性能的多目标优化模型。优化结果表明,挂钩垂向动态载荷最大值与标准差和吊耳的静态变形量与预载力标准差都有明显降低,文中提出的优化方法对控制排气系统振动和提升结构疲劳耐久性有重要的参考价值。

For improving the vibration performance of exhaust system in a passenger car,a FE model is built,on which the static and kinetics calculation,hanger location evaluation and the motion envelope calculation of exhaust system are conducted with Nastran code.Then a multi-objective optimization model for the vibration performance of exhaust system is set up and a simulation is performed with minimizing the peak vertical dynamic load and its standard deviation of hook and the static deformation and preload standard deviation of hangers as objective,the vibration isolation of hangers being not less than 20 dB as constraint,and the dynamic stiffness of hangers and corrugated pipes as design variables.The results show that the peak vertical dynamic load and its standard deviation of hook and the static deformation and preload standard deviation of hangers significantly reduce.The optimization method proposed is a valuable reference for controlling exhaust system vibration and improving its structural fatigue durability.