A Car Steering System Vibration Analysis And Structure Optimization

The vehicle vibration comfort is in line with the chassis, and the steering system which are important to the comfort and smooth of the vehicle. The steering wheel vibration influence the comfort of the vehicle, what's more, it can case the drivers tired. For the most company as they don't have dispensable analysis and optimization method as they design vehicle by their experience. So there is the realistic significance for analysis the joggling of steering system and optimization it.The thesis is about the chassis optimization designed by a company. My job is reaching on steering system joggling during brake and optimizing it to reduce joggling. I will make experiment, do modal analysis, do sensitivity analysis and do topology optimization.Firstly, the thesis will introduce the CAE using in project with the development of computer and numerical analysis theory. Then the thesis will discuss Finite element technology using in steering system at domestic and overseas. At the same time, the thesis will discuss the success and problem using in CAE in china.Secondly, the thesis do the Auto Wheel drum experiment to test the vibration frequency in different speed and brake force when clutch is connecting and breaking during brake. Through analysis finding the vibration frequency most concentrating in 30～35 Hz in different condition. Then the thesis tests the nature frequency by the modal experiment, and the result is the first and the second nature frequency are 31 Hz and 37 Hz. Compare it with the experiment and find out the first order nature frequency is close to the vibration frequency during braking. So it results in resonance and case the steering wheel joggling.Thirdly, draw the finite element model of the Steering System. The thesis will introduce how to select the mesh, add the property, control the constraints and so on. Then do the medal analysis by finite element method, and analysis the nature frequency of the steering system, especially first and second order nature frequency. At the same time, comparing the nature frequency tested by HyperWorks to the experiment, in order to check the accuracy of the software.Then the thesis will do the sensitivity analysis and discover the steering beam and steering stents influence greatly to the first and the second nature frequency of the Steering System. Further more, the thesis will increase the first nature frequency and rigidity as objective function, and reduce volume as constraint functions to do topology optimization. And the first order nature frequency increase from 31 Hz to 49 Hz; And the second order nature frequency increase from 31 Hz to 36 Hz. So the optimization satisfy the actual using request.Last but not least, do the stress analysis. Make sure all part of the steering system satisfy the design requirements.