Vibration Fatigue Life Analysis Of Steering Knuckle

Steering Knuckle is one of the main components of front steering axle. Bearing the front-axle load, Supporting and driving the front wheels rotate around the steering-yoke bolt are steering Knuckle's main functions. With the increase in speed of vehicles, vehicle parts to withstand the force of the working conditions have worsened. Steering knuckle bear the impact of changing loads, and the vehicle steering knuckle fatigue damage is becoming increasingly prominent. At present a large number of accidents damage from the steering knuckle caused by fatigue failure, Therefore, whether the vehicle steering knuckle meet the static strength and fatigue life requirements, is directly related to human security. The topic came from Zhejiang Science and Technology Department Major Funded Project-Development and Application of Digital Design & Analysis Platform of Shared Chassis. This paper studied Finite element analysis, and fatigue analysis of Mazda type steering knuckle. The main works and research results are as follows:1. Created a steering knuckle model in the PATRAN; also made the appropriate simplification on the model. Using tet10 element to mesh the model, defining of the material properties and restraint of the steering knuckle according to the actual situation. Analysis of how to use rbe2 to binding Knuckle's freedom, and how to applied load on the steering knuckle by use of rbe3.2. According to car driving situation, the author made force analysis of the steering knuckle in the three kinds of typical operating conditions, and gave the formula to calculate the force and torque under different conditions. Aiming at analyze the stress circumstances under typical dangerous working conditions of this vehicle type's Steering knuckle, using PATRAN and NASTRAN finite element analysis software to make analysis about it, and the results indicate that this steering knuckle can satisfy the static strength requirements.3. Aiming at analyzing the modal of Steering knuckle, studying the modal theory at first. Using PATRAN and NASTRAN finite element analysis software to make analysis about it, and the fore ten natural frequencies and corresponding modes were obtained through modal analysis. After Modal analysis, Authors also applied a unit stress on the steering knuckle to make frequency response analysis. It could be more intuitive to saw the natural frequency of steering knuckle and the relationship between the excitation frequencies from the results. Units of stress frequency response curve that is the system transfer function, the transfer function is to shift the basis of fatigue analysis section.4. Basing on the steering knuckle static and dynamic finite element analysis, considering the material fatigue properties average stress factors, Aiming at analyze the Fatigue Life of Steering knuckle using MSC.Fatigue software to make analysis about it.According to the analysis of chapter three it can be shown that the static strength of the steering knuckle can meet the requirements. From the analysis of chapter four it can be obtained the natural frequencies of the steering knuckle, and by frequency response analysis of the model the dynamic characteristics can be acquired. By solving out of the car in the B-road and C-road movement of the vibration fatigue life of steering knuckle, achieved to prediction Knuckle life at design stage.