某乘用车加速噪声CAE分析优化与试验验证

CAE Analysis Optimization and Test Verification of Acceleration Noise in a Passenger Car

在某乘用车的开发过程中,工程样车出现了加速噪声不达标的问题。为解决问题以保证不影响项目时间节点,敏感位置和原因需要快速确定。CAE方法是目前行业中解决工程问题最有效和常用的手段,本文即采用CAE方法对问题进行分析诊断和结构优化,首先进行整车有限元建模,整个模型包括车身声腔、内饰车身、底盘结构件、动力传动系统结构件、模态轮胎等,各零部件之间利用刚性单元或者弹性单元连接和组装。载荷为悬置被动端的加速度激励,输出的监测点为车内噪声和座椅导轨的振动水平。在加速噪声结果峰值附近进行节点贡献量分析,针对贡献量大的位置提出了优化方案。对比优化前后的车内加速噪声结果,表明优化改进后加速噪声明显降低,达成了整车NVH目标。该工作体现了利用整车CAE仿真分析进行问题诊断和设计优化,可以极大地提高问题解决效率,降低试验成本,有利于缩短开发周期。

During the development of a passenger vehicle program,an OTS prototype vehicle failed to meet the acceleration noise target.In order to resolve the issue and avoid the potential delay,the root causes need to be identified quickly.Since the CAE method is an effective and commonly used method to solve engineering problems in the automotive industry,this paper applies the CAE method to analyze the problem,identify the root cause,and optimize the structure.Firstly,a finite element full vehicle model is established,which includes the body cavity,interior body,chassis structure,powertrain system,modal tire,etc.The full vehicle model is assembled using elastic and rigid connections.The applied load is the acceleration excitation which is applied at the passive side of the engine mounts,and the output monitoring quantities are the interior noise level and the seat track vibration level.The contribution of nodes is analyzed near the peak value of the acceleration noise,and an optimization scheme is proposed for the areas with large contributions.Comparing the level of the acceleration noise before and after the optimization,it shows that the acceleration noise after the optimization is significantly reduced,and the NVH target of the vehicle is achieved.This work shows that the problem diagnosis and design optimization by CAE simulation for a full vehicle can greatly improve the efficiency of the problem solving,reduce the cost of testing and shorten the development cycle.