The Analysis And Optimization Of The Steering Knuckle Based On Reliability

Steering knuckle plays a key role in steering axle for connecting between itself and other important parts in vehicle, including suspensions, brakes and steering system. Its main functions include bearing vehicle’s front weight, and also bearing and driving the kingpin in front wheels, which can ensure the flexibility for steering, stability for driving and precision for directing. Key position of steering knuckle in the automobile suspension and all these functions mentioned above contribute to steering knuckle’s complex structure and shape. Therefore, the failure steering knuckle can cause bad consequences like losing vehicle’s steering ability immediately. During driving, steering knuckle is under sorts of load, such as statistic load from vehicle itself, constraints from other parts of vehicle and the impact passing from the road. All these loads not only vary with working conditions, but also change with random road conditions. Therefore, researches on steering knuckle’s reliability and optimization design have significant meanings.The thesis is based on the vehicle’s front double-wishbone independent suspension. Aiming at its key part’s- steering knuckle- problem of optimization design, completed following research works:(1) Dynamic simulation analysis. By understanding the structure of vehicle’s front independent suspension, and based on its three-dimensional model determined suspension system’s parameters to establish the suspension’s dynamic model for dynamic simulation and get the steering knuckle’s loading situation under each working condition for finite element analysis of steering knuckle.(2) Established steering knuckle’s finite element analysis model and completed its static strength analysis. The results show that steering knuckle meets the requirements strength. Besides, the stress and strain data of steering knuckle is extracted for analyzing to select dangerous working conditions for its subsequent reliability analysis and optimization design.(3) Reliability and sensitivity analysis. Random factors affect steering knuckle’s reliability are determined. By combining it with finite element analyzed results for reliability analysis. And by combining it with optimization goal for random factors’ sensitivity analysis. And then by selecting appropriate design parameters to provide basis for steering knuckle’s subsequent optimization.(4) Optimization design. According to the selected design parameters after sensitivity analysis, and by setting reducing weight as a goal and satisfying the requirement of strength, stiffness and geometry as constraint conditions, the optimized mathematical model is built and the lightweight design is completed. Finally, after static strength and reliability analysis, the results show that the optimized steering knuckle still meets the requirements of strength and stiffness, and the total weight reduced significantly while remaining high reliability, which realized the goal of steering knuckle’s lightweight design.This thesis is about solving a practical engineering problem by using theoretical knowledge and simulation analysis, and by combining practical production process, realized the goal of steering knuckle’s optimization design, which has a significant meaning for similar engineering optimization problem that needs to take reliability into consideration.