Optimization Design For Key Structure Performance Indicators Of Vehicle Based On Interval Uncertainty

The performance of vehicle structure depends on the quality of the correspondingparameters to a large extent. It is of great significance for enhancing whole performanceof vehicle structure and decreasing design and manufacturing cost by using efficientmethods to optimize the corresponding key parameters in vehicle structure. Meanwh ile,considering the uncertainties in optimization design will have important influence onincreasing the reliability of structure performance. Nowadays, probabilistic model is themost popular one for uncertain structure optimization of vehicle, which can well describethe random uncertainty of system. Nevertheless, due to the difficulties of acquiringuncertain information and computational efficiency, several optimization methods basedon probabilistic model cannot be applied into vehicle structure design directly. Oncontrast, interval model just needs much less uncertain information, which only requiresthe up and low bounds of uncertain parameters. Therefore, it will be much more suitablefor engineering optimization problems and make great point on vehicle structure design.The paper has carried on the corresponding research about the theory of intervaluncertain optimization method and its application. The main work in this paper is asfollowed:(1) Two uncertain optimization methods based on tolerance were proposed, whichwere efficient tools for interval uncertain synchronous design between design variablesand tolerance. In the first presented method, the interval middle point represents themean value of objective function and tolerance estimation factor could describe tolerancevalue of variables. The second method treated the tolerance estimation factor as theobjective and regarded nominal performance as constraints to maximize the tolerance ofnominal performance in the worst case.(2) The proposed method was applied into uncertain optimization design of vehicleride comfort. At first, three uncertain optimization models of vehicle ride comfortcomposed of two, five and eight degrees freedom were builtand verified by a real vehicleexperiment. Then, the stiffness and damping of automobile suspension were regarded asinterval variables and the corresponding interval uncertain optimization had beenaccomplished, which both optimized the vehicle ride comfort and improved themanufacturing and assembly process.(3) By using the interval methods based tolerance, two key problems in vehicle handling stability were optimized, which enhanced the performance of front suspensionposition parameters and whole vehicle handling stability. Moreover, the multi-rigid-bodysimulation and optimization models on vehicle steering stability, optimizing the positionparameters of front suspension and improving the manufacturing and assembly process,were built.(4) The finite element models of front and side crashworthiness were established,which were used to optimize based on the proposed methods in this paper. In addition,the vehicle safety optimization model was used to optimize structural panels of vehiclebody through interval uncertain optimization methods, which enhanced the performanceof body’s absorbing components.